[feature] support processing of (many) more media types (#3090)

* initial work replacing our media decoding / encoding pipeline with ffprobe + ffmpeg

* specify the video codec to use when generating static image from emoji

* update go-storage library (fixes incompatibility after updating go-iotools)

* maintain image aspect ratio when generating a thumbnail for it

* update readme to show go-ffmpreg

* fix a bunch of media tests, move filesize checking to callers of media manager for more flexibility

* remove extra debug from error message

* fix up incorrect function signatures

* update PutFile to just use regular file copy, as changes are file is on separate partition

* fix remaining tests, remove some unneeded tests now we're working with ffmpeg/ffprobe

* update more tests, add more code comments

* add utilities to generate processed emoji / media outputs

* fix remaining tests

* add test for opus media file, add license header to utility cmds

* limit the number of concurrently available ffmpeg / ffprobe instances

* reduce number of instances

* further reduce number of instances

* fix envparsing test with configuration variables

* update docs and configuration with new media-{local,remote}-max-size variables

15 files changed, 0 insertions, 4203 deletions

diff --git a/vendor/golang.org/x/image/riff/riff.go b/vendor/golang.org/x/image/riff/riff.go
deleted file mode 100644
index 38dc0e568..000000000
--- a/vendor/golang.org/x/image/riff/riff.go
+++ /dev/null
@@ -1,193 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package riff implements the Resource Interchange File Format, used by media
-// formats such as AVI, WAVE and WEBP.
-//
-// A RIFF stream contains a sequence of chunks. Each chunk consists of an 8-byte
-// header (containing a 4-byte chunk type and a 4-byte chunk length), the chunk
-// data (presented as an io.Reader), and some padding bytes.
-//
-// A detailed description of the format is at
-// http://www.tactilemedia.com/info/MCI_Control_Info.html
-package riff // import "golang.org/x/image/riff"
-
-import (
-	"errors"
-	"io"
-	"io/ioutil"
-	"math"
-)
-
-var (
-	errMissingPaddingByte     = errors.New("riff: missing padding byte")
-	errMissingRIFFChunkHeader = errors.New("riff: missing RIFF chunk header")
-	errListSubchunkTooLong    = errors.New("riff: list subchunk too long")
-	errShortChunkData         = errors.New("riff: short chunk data")
-	errShortChunkHeader       = errors.New("riff: short chunk header")
-	errStaleReader            = errors.New("riff: stale reader")
-)
-
-// u32 decodes the first four bytes of b as a little-endian integer.
-func u32(b []byte) uint32 {
-	return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
-}
-
-const chunkHeaderSize = 8
-
-// FourCC is a four character code.
-type FourCC [4]byte
-
-// LIST is the "LIST" FourCC.
-var LIST = FourCC{'L', 'I', 'S', 'T'}
-
-// NewReader returns the RIFF stream's form type, such as "AVI " or "WAVE", and
-// its chunks as a *Reader.
-func NewReader(r io.Reader) (formType FourCC, data *Reader, err error) {
-	var buf [chunkHeaderSize]byte
-	if _, err := io.ReadFull(r, buf[:]); err != nil {
-		if err == io.EOF || err == io.ErrUnexpectedEOF {
-			err = errMissingRIFFChunkHeader
-		}
-		return FourCC{}, nil, err
-	}
-	if buf[0] != 'R' || buf[1] != 'I' || buf[2] != 'F' || buf[3] != 'F' {
-		return FourCC{}, nil, errMissingRIFFChunkHeader
-	}
-	return NewListReader(u32(buf[4:]), r)
-}
-
-// NewListReader returns a LIST chunk's list type, such as "movi" or "wavl",
-// and its chunks as a *Reader.
-func NewListReader(chunkLen uint32, chunkData io.Reader) (listType FourCC, data *Reader, err error) {
-	if chunkLen < 4 {
-		return FourCC{}, nil, errShortChunkData
-	}
-	z := &Reader{r: chunkData}
-	if _, err := io.ReadFull(chunkData, z.buf[:4]); err != nil {
-		if err == io.EOF || err == io.ErrUnexpectedEOF {
-			err = errShortChunkData
-		}
-		return FourCC{}, nil, err
-	}
-	z.totalLen = chunkLen - 4
-	return FourCC{z.buf[0], z.buf[1], z.buf[2], z.buf[3]}, z, nil
-}
-
-// Reader reads chunks from an underlying io.Reader.
-type Reader struct {
-	r   io.Reader
-	err error
-
-	totalLen uint32
-	chunkLen uint32
-
-	chunkReader *chunkReader
-	buf         [chunkHeaderSize]byte
-	padded      bool
-}
-
-// Next returns the next chunk's ID, length and data. It returns io.EOF if there
-// are no more chunks. The io.Reader returned becomes stale after the next Next
-// call, and should no longer be used.
-//
-// It is valid to call Next even if all of the previous chunk's data has not
-// been read.
-func (z *Reader) Next() (chunkID FourCC, chunkLen uint32, chunkData io.Reader, err error) {
-	if z.err != nil {
-		return FourCC{}, 0, nil, z.err
-	}
-
-	// Drain the rest of the previous chunk.
-	if z.chunkLen != 0 {
-		want := z.chunkLen
-		var got int64
-		got, z.err = io.Copy(ioutil.Discard, z.chunkReader)
-		if z.err == nil && uint32(got) != want {
-			z.err = errShortChunkData
-		}
-		if z.err != nil {
-			return FourCC{}, 0, nil, z.err
-		}
-	}
-	z.chunkReader = nil
-	if z.padded {
-		if z.totalLen == 0 {
-			z.err = errListSubchunkTooLong
-			return FourCC{}, 0, nil, z.err
-		}
-		z.totalLen--
-		_, z.err = io.ReadFull(z.r, z.buf[:1])
-		if z.err != nil {
-			if z.err == io.EOF {
-				z.err = errMissingPaddingByte
-			}
-			return FourCC{}, 0, nil, z.err
-		}
-	}
-
-	// We are done if we have no more data.
-	if z.totalLen == 0 {
-		z.err = io.EOF
-		return FourCC{}, 0, nil, z.err
-	}
-
-	// Read the next chunk header.
-	if z.totalLen < chunkHeaderSize {
-		z.err = errShortChunkHeader
-		return FourCC{}, 0, nil, z.err
-	}
-	z.totalLen -= chunkHeaderSize
-	if _, z.err = io.ReadFull(z.r, z.buf[:chunkHeaderSize]); z.err != nil {
-		if z.err == io.EOF || z.err == io.ErrUnexpectedEOF {
-			z.err = errShortChunkHeader
-		}
-		return FourCC{}, 0, nil, z.err
-	}
-	chunkID = FourCC{z.buf[0], z.buf[1], z.buf[2], z.buf[3]}
-	z.chunkLen = u32(z.buf[4:])
-	if z.chunkLen > z.totalLen {
-		z.err = errListSubchunkTooLong
-		return FourCC{}, 0, nil, z.err
-	}
-	z.padded = z.chunkLen&1 == 1
-	z.chunkReader = &chunkReader{z}
-	return chunkID, z.chunkLen, z.chunkReader, nil
-}
-
-type chunkReader struct {
-	z *Reader
-}
-
-func (c *chunkReader) Read(p []byte) (int, error) {
-	if c != c.z.chunkReader {
-		return 0, errStaleReader
-	}
-	z := c.z
-	if z.err != nil {
-		if z.err == io.EOF {
-			return 0, errStaleReader
-		}
-		return 0, z.err
-	}
-
-	n := int(z.chunkLen)
-	if n == 0 {
-		return 0, io.EOF
-	}
-	if n < 0 {
-		// Converting uint32 to int overflowed.
-		n = math.MaxInt32
-	}
-	if n > len(p) {
-		n = len(p)
-	}
-	n, err := z.r.Read(p[:n])
-	z.totalLen -= uint32(n)
-	z.chunkLen -= uint32(n)
-	if err != io.EOF {
-		z.err = err
-	}
-	return n, err
-}
diff --git a/vendor/golang.org/x/image/vp8/decode.go b/vendor/golang.org/x/image/vp8/decode.go
deleted file mode 100644
index 2aa9fee03..000000000
--- a/vendor/golang.org/x/image/vp8/decode.go
+++ /dev/null
@@ -1,403 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package vp8 implements a decoder for the VP8 lossy image format.
-//
-// The VP8 specification is RFC 6386.
-package vp8 // import "golang.org/x/image/vp8"
-
-// This file implements the top-level decoding algorithm.
-
-import (
-	"errors"
-	"image"
-	"io"
-)
-
-// limitReader wraps an io.Reader to read at most n bytes from it.
-type limitReader struct {
-	r io.Reader
-	n int
-}
-
-// ReadFull reads exactly len(p) bytes into p.
-func (r *limitReader) ReadFull(p []byte) error {
-	if len(p) > r.n {
-		return io.ErrUnexpectedEOF
-	}
-	n, err := io.ReadFull(r.r, p)
-	r.n -= n
-	return err
-}
-
-// FrameHeader is a frame header, as specified in section 9.1.
-type FrameHeader struct {
-	KeyFrame          bool
-	VersionNumber     uint8
-	ShowFrame         bool
-	FirstPartitionLen uint32
-	Width             int
-	Height            int
-	XScale            uint8
-	YScale            uint8
-}
-
-const (
-	nSegment     = 4
-	nSegmentProb = 3
-)
-
-// segmentHeader holds segment-related header information.
-type segmentHeader struct {
-	useSegment     bool
-	updateMap      bool
-	relativeDelta  bool
-	quantizer      [nSegment]int8
-	filterStrength [nSegment]int8
-	prob           [nSegmentProb]uint8
-}
-
-const (
-	nRefLFDelta  = 4
-	nModeLFDelta = 4
-)
-
-// filterHeader holds filter-related header information.
-type filterHeader struct {
-	simple          bool
-	level           int8
-	sharpness       uint8
-	useLFDelta      bool
-	refLFDelta      [nRefLFDelta]int8
-	modeLFDelta     [nModeLFDelta]int8
-	perSegmentLevel [nSegment]int8
-}
-
-// mb is the per-macroblock decode state. A decoder maintains mbw+1 of these
-// as it is decoding macroblocks left-to-right and top-to-bottom: mbw for the
-// macroblocks in the row above, and one for the macroblock to the left.
-type mb struct {
-	// pred is the predictor mode for the 4 bottom or right 4x4 luma regions.
-	pred [4]uint8
-	// nzMask is a mask of 8 bits: 4 for the bottom or right 4x4 luma regions,
-	// and 2 + 2 for the bottom or right 4x4 chroma regions. A 1 bit indicates
-	// that region has non-zero coefficients.
-	nzMask uint8
-	// nzY16 is a 0/1 value that is 1 if the macroblock used Y16 prediction and
-	// had non-zero coefficients.
-	nzY16 uint8
-}
-
-// Decoder decodes VP8 bitstreams into frames. Decoding one frame consists of
-// calling Init, DecodeFrameHeader and then DecodeFrame in that order.
-// A Decoder can be re-used to decode multiple frames.
-type Decoder struct {
-	// r is the input bitsream.
-	r limitReader
-	// scratch is a scratch buffer.
-	scratch [8]byte
-	// img is the YCbCr image to decode into.
-	img *image.YCbCr
-	// mbw and mbh are the number of 16x16 macroblocks wide and high the image is.
-	mbw, mbh int
-	// frameHeader is the frame header. When decoding multiple frames,
-	// frames that aren't key frames will inherit the Width, Height,
-	// XScale and YScale of the most recent key frame.
-	frameHeader FrameHeader
-	// Other headers.
-	segmentHeader segmentHeader
-	filterHeader  filterHeader
-	// The image data is divided into a number of independent partitions.
-	// There is 1 "first partition" and between 1 and 8 "other partitions"
-	// for coefficient data.
-	fp  partition
-	op  [8]partition
-	nOP int
-	// Quantization factors.
-	quant [nSegment]quant
-	// DCT/WHT coefficient decoding probabilities.
-	tokenProb   [nPlane][nBand][nContext][nProb]uint8
-	useSkipProb bool
-	skipProb    uint8
-	// Loop filter parameters.
-	filterParams      [nSegment][2]filterParam
-	perMBFilterParams []filterParam
-
-	// The eight fields below relate to the current macroblock being decoded.
-	//
-	// Segment-based adjustments.
-	segment int
-	// Per-macroblock state for the macroblock immediately left of and those
-	// macroblocks immediately above the current macroblock.
-	leftMB mb
-	upMB   []mb
-	// Bitmasks for which 4x4 regions of coeff contain non-zero coefficients.
-	nzDCMask, nzACMask uint32
-	// Predictor modes.
-	usePredY16 bool // The libwebp C code calls this !is_i4x4_.
-	predY16    uint8
-	predC8     uint8
-	predY4     [4][4]uint8
-
-	// The two fields below form a workspace for reconstructing a macroblock.
-	// Their specific sizes are documented in reconstruct.go.
-	coeff [1*16*16 + 2*8*8 + 1*4*4]int16
-	ybr   [1 + 16 + 1 + 8][32]uint8
-}
-
-// NewDecoder returns a new Decoder.
-func NewDecoder() *Decoder {
-	return &Decoder{}
-}
-
-// Init initializes the decoder to read at most n bytes from r.
-func (d *Decoder) Init(r io.Reader, n int) {
-	d.r = limitReader{r, n}
-}
-
-// DecodeFrameHeader decodes the frame header.
-func (d *Decoder) DecodeFrameHeader() (fh FrameHeader, err error) {
-	// All frame headers are at least 3 bytes long.
-	b := d.scratch[:3]
-	if err = d.r.ReadFull(b); err != nil {
-		return
-	}
-	d.frameHeader.KeyFrame = (b[0] & 1) == 0
-	d.frameHeader.VersionNumber = (b[0] >> 1) & 7
-	d.frameHeader.ShowFrame = (b[0]>>4)&1 == 1
-	d.frameHeader.FirstPartitionLen = uint32(b[0])>>5 | uint32(b[1])<<3 | uint32(b[2])<<11
-	if !d.frameHeader.KeyFrame {
-		return d.frameHeader, nil
-	}
-	// Frame headers for key frames are an additional 7 bytes long.
-	b = d.scratch[:7]
-	if err = d.r.ReadFull(b); err != nil {
-		return
-	}
-	// Check the magic sync code.
-	if b[0] != 0x9d || b[1] != 0x01 || b[2] != 0x2a {
-		err = errors.New("vp8: invalid format")
-		return
-	}
-	d.frameHeader.Width = int(b[4]&0x3f)<<8 | int(b[3])
-	d.frameHeader.Height = int(b[6]&0x3f)<<8 | int(b[5])
-	d.frameHeader.XScale = b[4] >> 6
-	d.frameHeader.YScale = b[6] >> 6
-	d.mbw = (d.frameHeader.Width + 0x0f) >> 4
-	d.mbh = (d.frameHeader.Height + 0x0f) >> 4
-	d.segmentHeader = segmentHeader{
-		prob: [3]uint8{0xff, 0xff, 0xff},
-	}
-	d.tokenProb = defaultTokenProb
-	d.segment = 0
-	return d.frameHeader, nil
-}
-
-// ensureImg ensures that d.img is large enough to hold the decoded frame.
-func (d *Decoder) ensureImg() {
-	if d.img != nil {
-		p0, p1 := d.img.Rect.Min, d.img.Rect.Max
-		if p0.X == 0 && p0.Y == 0 && p1.X >= 16*d.mbw && p1.Y >= 16*d.mbh {
-			return
-		}
-	}
-	m := image.NewYCbCr(image.Rect(0, 0, 16*d.mbw, 16*d.mbh), image.YCbCrSubsampleRatio420)
-	d.img = m.SubImage(image.Rect(0, 0, d.frameHeader.Width, d.frameHeader.Height)).(*image.YCbCr)
-	d.perMBFilterParams = make([]filterParam, d.mbw*d.mbh)
-	d.upMB = make([]mb, d.mbw)
-}
-
-// parseSegmentHeader parses the segment header, as specified in section 9.3.
-func (d *Decoder) parseSegmentHeader() {
-	d.segmentHeader.useSegment = d.fp.readBit(uniformProb)
-	if !d.segmentHeader.useSegment {
-		d.segmentHeader.updateMap = false
-		return
-	}
-	d.segmentHeader.updateMap = d.fp.readBit(uniformProb)
-	if d.fp.readBit(uniformProb) {
-		d.segmentHeader.relativeDelta = !d.fp.readBit(uniformProb)
-		for i := range d.segmentHeader.quantizer {
-			d.segmentHeader.quantizer[i] = int8(d.fp.readOptionalInt(uniformProb, 7))
-		}
-		for i := range d.segmentHeader.filterStrength {
-			d.segmentHeader.filterStrength[i] = int8(d.fp.readOptionalInt(uniformProb, 6))
-		}
-	}
-	if !d.segmentHeader.updateMap {
-		return
-	}
-	for i := range d.segmentHeader.prob {
-		if d.fp.readBit(uniformProb) {
-			d.segmentHeader.prob[i] = uint8(d.fp.readUint(uniformProb, 8))
-		} else {
-			d.segmentHeader.prob[i] = 0xff
-		}
-	}
-}
-
-// parseFilterHeader parses the filter header, as specified in section 9.4.
-func (d *Decoder) parseFilterHeader() {
-	d.filterHeader.simple = d.fp.readBit(uniformProb)
-	d.filterHeader.level = int8(d.fp.readUint(uniformProb, 6))
-	d.filterHeader.sharpness = uint8(d.fp.readUint(uniformProb, 3))
-	d.filterHeader.useLFDelta = d.fp.readBit(uniformProb)
-	if d.filterHeader.useLFDelta && d.fp.readBit(uniformProb) {
-		for i := range d.filterHeader.refLFDelta {
-			d.filterHeader.refLFDelta[i] = int8(d.fp.readOptionalInt(uniformProb, 6))
-		}
-		for i := range d.filterHeader.modeLFDelta {
-			d.filterHeader.modeLFDelta[i] = int8(d.fp.readOptionalInt(uniformProb, 6))
-		}
-	}
-	if d.filterHeader.level == 0 {
-		return
-	}
-	if d.segmentHeader.useSegment {
-		for i := range d.filterHeader.perSegmentLevel {
-			strength := d.segmentHeader.filterStrength[i]
-			if d.segmentHeader.relativeDelta {
-				strength += d.filterHeader.level
-			}
-			d.filterHeader.perSegmentLevel[i] = strength
-		}
-	} else {
-		d.filterHeader.perSegmentLevel[0] = d.filterHeader.level
-	}
-	d.computeFilterParams()
-}
-
-// parseOtherPartitions parses the other partitions, as specified in section 9.5.
-func (d *Decoder) parseOtherPartitions() error {
-	const maxNOP = 1 << 3
-	var partLens [maxNOP]int
-	d.nOP = 1 << d.fp.readUint(uniformProb, 2)
-
-	// The final partition length is implied by the remaining chunk data
-	// (d.r.n) and the other d.nOP-1 partition lengths. Those d.nOP-1 partition
-	// lengths are stored as 24-bit uints, i.e. up to 16 MiB per partition.
-	n := 3 * (d.nOP - 1)
-	partLens[d.nOP-1] = d.r.n - n
-	if partLens[d.nOP-1] < 0 {
-		return io.ErrUnexpectedEOF
-	}
-	if n > 0 {
-		buf := make([]byte, n)
-		if err := d.r.ReadFull(buf); err != nil {
-			return err
-		}
-		for i := 0; i < d.nOP-1; i++ {
-			pl := int(buf[3*i+0]) | int(buf[3*i+1])<<8 | int(buf[3*i+2])<<16
-			if pl > partLens[d.nOP-1] {
-				return io.ErrUnexpectedEOF
-			}
-			partLens[i] = pl
-			partLens[d.nOP-1] -= pl
-		}
-	}
-
-	// We check if the final partition length can also fit into a 24-bit uint.
-	// Strictly speaking, this isn't part of the spec, but it guards against a
-	// malicious WEBP image that is too large to ReadFull the encoded DCT
-	// coefficients into memory, whether that's because the actual WEBP file is
-	// too large, or whether its RIFF metadata lists too large a chunk.
-	if 1<<24 <= partLens[d.nOP-1] {
-		return errors.New("vp8: too much data to decode")
-	}
-
-	buf := make([]byte, d.r.n)
-	if err := d.r.ReadFull(buf); err != nil {
-		return err
-	}
-	for i, pl := range partLens {
-		if i == d.nOP {
-			break
-		}
-		d.op[i].init(buf[:pl])
-		buf = buf[pl:]
-	}
-	return nil
-}
-
-// parseOtherHeaders parses header information other than the frame header.
-func (d *Decoder) parseOtherHeaders() error {
-	// Initialize and parse the first partition.
-	firstPartition := make([]byte, d.frameHeader.FirstPartitionLen)
-	if err := d.r.ReadFull(firstPartition); err != nil {
-		return err
-	}
-	d.fp.init(firstPartition)
-	if d.frameHeader.KeyFrame {
-		// Read and ignore the color space and pixel clamp values. They are
-		// specified in section 9.2, but are unimplemented.
-		d.fp.readBit(uniformProb)
-		d.fp.readBit(uniformProb)
-	}
-	d.parseSegmentHeader()
-	d.parseFilterHeader()
-	if err := d.parseOtherPartitions(); err != nil {
-		return err
-	}
-	d.parseQuant()
-	if !d.frameHeader.KeyFrame {
-		// Golden and AltRef frames are specified in section 9.7.
-		// TODO(nigeltao): implement. Note that they are only used for video, not still images.
-		return errors.New("vp8: Golden / AltRef frames are not implemented")
-	}
-	// Read and ignore the refreshLastFrameBuffer bit, specified in section 9.8.
-	// It applies only to video, and not still images.
-	d.fp.readBit(uniformProb)
-	d.parseTokenProb()
-	d.useSkipProb = d.fp.readBit(uniformProb)
-	if d.useSkipProb {
-		d.skipProb = uint8(d.fp.readUint(uniformProb, 8))
-	}
-	if d.fp.unexpectedEOF {
-		return io.ErrUnexpectedEOF
-	}
-	return nil
-}
-
-// DecodeFrame decodes the frame and returns it as an YCbCr image.
-// The image's contents are valid up until the next call to Decoder.Init.
-func (d *Decoder) DecodeFrame() (*image.YCbCr, error) {
-	d.ensureImg()
-	if err := d.parseOtherHeaders(); err != nil {
-		return nil, err
-	}
-	// Reconstruct the rows.
-	for mbx := 0; mbx < d.mbw; mbx++ {
-		d.upMB[mbx] = mb{}
-	}
-	for mby := 0; mby < d.mbh; mby++ {
-		d.leftMB = mb{}
-		for mbx := 0; mbx < d.mbw; mbx++ {
-			skip := d.reconstruct(mbx, mby)
-			fs := d.filterParams[d.segment][btou(!d.usePredY16)]
-			fs.inner = fs.inner || !skip
-			d.perMBFilterParams[d.mbw*mby+mbx] = fs
-		}
-	}
-	if d.fp.unexpectedEOF {
-		return nil, io.ErrUnexpectedEOF
-	}
-	for i := 0; i < d.nOP; i++ {
-		if d.op[i].unexpectedEOF {
-			return nil, io.ErrUnexpectedEOF
-		}
-	}
-	// Apply the loop filter.
-	//
-	// Even if we are using per-segment levels, section 15 says that "loop
-	// filtering must be skipped entirely if loop_filter_level at either the
-	// frame header level or macroblock override level is 0".
-	if d.filterHeader.level != 0 {
-		if d.filterHeader.simple {
-			d.simpleFilter()
-		} else {
-			d.normalFilter()
-		}
-	}
-	return d.img, nil
-}
diff --git a/vendor/golang.org/x/image/vp8/filter.go b/vendor/golang.org/x/image/vp8/filter.go
deleted file mode 100644
index e34a811b1..000000000
--- a/vendor/golang.org/x/image/vp8/filter.go
+++ /dev/null
@@ -1,273 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package vp8
-
-// filter2 modifies a 2-pixel wide or 2-pixel high band along an edge.
-func filter2(pix []byte, level, index, iStep, jStep int) {
-	for n := 16; n > 0; n, index = n-1, index+iStep {
-		p1 := int(pix[index-2*jStep])
-		p0 := int(pix[index-1*jStep])
-		q0 := int(pix[index+0*jStep])
-		q1 := int(pix[index+1*jStep])
-		if abs(p0-q0)<<1+abs(p1-q1)>>1 > level {
-			continue
-		}
-		a := 3*(q0-p0) + clamp127(p1-q1)
-		a1 := clamp15((a + 4) >> 3)
-		a2 := clamp15((a + 3) >> 3)
-		pix[index-1*jStep] = clamp255(p0 + a2)
-		pix[index+0*jStep] = clamp255(q0 - a1)
-	}
-}
-
-// filter246 modifies a 2-, 4- or 6-pixel wide or high band along an edge.
-func filter246(pix []byte, n, level, ilevel, hlevel, index, iStep, jStep int, fourNotSix bool) {
-	for ; n > 0; n, index = n-1, index+iStep {
-		p3 := int(pix[index-4*jStep])
-		p2 := int(pix[index-3*jStep])
-		p1 := int(pix[index-2*jStep])
-		p0 := int(pix[index-1*jStep])
-		q0 := int(pix[index+0*jStep])
-		q1 := int(pix[index+1*jStep])
-		q2 := int(pix[index+2*jStep])
-		q3 := int(pix[index+3*jStep])
-		if abs(p0-q0)<<1+abs(p1-q1)>>1 > level {
-			continue
-		}
-		if abs(p3-p2) > ilevel ||
-			abs(p2-p1) > ilevel ||
-			abs(p1-p0) > ilevel ||
-			abs(q1-q0) > ilevel ||
-			abs(q2-q1) > ilevel ||
-			abs(q3-q2) > ilevel {
-			continue
-		}
-		if abs(p1-p0) > hlevel || abs(q1-q0) > hlevel {
-			// Filter 2 pixels.
-			a := 3*(q0-p0) + clamp127(p1-q1)
-			a1 := clamp15((a + 4) >> 3)
-			a2 := clamp15((a + 3) >> 3)
-			pix[index-1*jStep] = clamp255(p0 + a2)
-			pix[index+0*jStep] = clamp255(q0 - a1)
-		} else if fourNotSix {
-			// Filter 4 pixels.
-			a := 3 * (q0 - p0)
-			a1 := clamp15((a + 4) >> 3)
-			a2 := clamp15((a + 3) >> 3)
-			a3 := (a1 + 1) >> 1
-			pix[index-2*jStep] = clamp255(p1 + a3)
-			pix[index-1*jStep] = clamp255(p0 + a2)
-			pix[index+0*jStep] = clamp255(q0 - a1)
-			pix[index+1*jStep] = clamp255(q1 - a3)
-		} else {
-			// Filter 6 pixels.
-			a := clamp127(3*(q0-p0) + clamp127(p1-q1))
-			a1 := (27*a + 63) >> 7
-			a2 := (18*a + 63) >> 7
-			a3 := (9*a + 63) >> 7
-			pix[index-3*jStep] = clamp255(p2 + a3)
-			pix[index-2*jStep] = clamp255(p1 + a2)
-			pix[index-1*jStep] = clamp255(p0 + a1)
-			pix[index+0*jStep] = clamp255(q0 - a1)
-			pix[index+1*jStep] = clamp255(q1 - a2)
-			pix[index+2*jStep] = clamp255(q2 - a3)
-		}
-	}
-}
-
-// simpleFilter implements the simple filter, as specified in section 15.2.
-func (d *Decoder) simpleFilter() {
-	for mby := 0; mby < d.mbh; mby++ {
-		for mbx := 0; mbx < d.mbw; mbx++ {
-			f := d.perMBFilterParams[d.mbw*mby+mbx]
-			if f.level == 0 {
-				continue
-			}
-			l := int(f.level)
-			yIndex := (mby*d.img.YStride + mbx) * 16
-			if mbx > 0 {
-				filter2(d.img.Y, l+4, yIndex, d.img.YStride, 1)
-			}
-			if f.inner {
-				filter2(d.img.Y, l, yIndex+0x4, d.img.YStride, 1)
-				filter2(d.img.Y, l, yIndex+0x8, d.img.YStride, 1)
-				filter2(d.img.Y, l, yIndex+0xc, d.img.YStride, 1)
-			}
-			if mby > 0 {
-				filter2(d.img.Y, l+4, yIndex, 1, d.img.YStride)
-			}
-			if f.inner {
-				filter2(d.img.Y, l, yIndex+d.img.YStride*0x4, 1, d.img.YStride)
-				filter2(d.img.Y, l, yIndex+d.img.YStride*0x8, 1, d.img.YStride)
-				filter2(d.img.Y, l, yIndex+d.img.YStride*0xc, 1, d.img.YStride)
-			}
-		}
-	}
-}
-
-// normalFilter implements the normal filter, as specified in section 15.3.
-func (d *Decoder) normalFilter() {
-	for mby := 0; mby < d.mbh; mby++ {
-		for mbx := 0; mbx < d.mbw; mbx++ {
-			f := d.perMBFilterParams[d.mbw*mby+mbx]
-			if f.level == 0 {
-				continue
-			}
-			l, il, hl := int(f.level), int(f.ilevel), int(f.hlevel)
-			yIndex := (mby*d.img.YStride + mbx) * 16
-			cIndex := (mby*d.img.CStride + mbx) * 8
-			if mbx > 0 {
-				filter246(d.img.Y, 16, l+4, il, hl, yIndex, d.img.YStride, 1, false)
-				filter246(d.img.Cb, 8, l+4, il, hl, cIndex, d.img.CStride, 1, false)
-				filter246(d.img.Cr, 8, l+4, il, hl, cIndex, d.img.CStride, 1, false)
-			}
-			if f.inner {
-				filter246(d.img.Y, 16, l, il, hl, yIndex+0x4, d.img.YStride, 1, true)
-				filter246(d.img.Y, 16, l, il, hl, yIndex+0x8, d.img.YStride, 1, true)
-				filter246(d.img.Y, 16, l, il, hl, yIndex+0xc, d.img.YStride, 1, true)
-				filter246(d.img.Cb, 8, l, il, hl, cIndex+0x4, d.img.CStride, 1, true)
-				filter246(d.img.Cr, 8, l, il, hl, cIndex+0x4, d.img.CStride, 1, true)
-			}
-			if mby > 0 {
-				filter246(d.img.Y, 16, l+4, il, hl, yIndex, 1, d.img.YStride, false)
-				filter246(d.img.Cb, 8, l+4, il, hl, cIndex, 1, d.img.CStride, false)
-				filter246(d.img.Cr, 8, l+4, il, hl, cIndex, 1, d.img.CStride, false)
-			}
-			if f.inner {
-				filter246(d.img.Y, 16, l, il, hl, yIndex+d.img.YStride*0x4, 1, d.img.YStride, true)
-				filter246(d.img.Y, 16, l, il, hl, yIndex+d.img.YStride*0x8, 1, d.img.YStride, true)
-				filter246(d.img.Y, 16, l, il, hl, yIndex+d.img.YStride*0xc, 1, d.img.YStride, true)
-				filter246(d.img.Cb, 8, l, il, hl, cIndex+d.img.CStride*0x4, 1, d.img.CStride, true)
-				filter246(d.img.Cr, 8, l, il, hl, cIndex+d.img.CStride*0x4, 1, d.img.CStride, true)
-			}
-		}
-	}
-}
-
-// filterParam holds the loop filter parameters for a macroblock.
-type filterParam struct {
-	// The first three fields are thresholds used by the loop filter to smooth
-	// over the edges and interior of a macroblock. level is used by both the
-	// simple and normal filters. The inner level and high edge variance level
-	// are only used by the normal filter.
-	level, ilevel, hlevel uint8
-	// inner is whether the inner loop filter cannot be optimized out as a
-	// no-op for this particular macroblock.
-	inner bool
-}
-
-// computeFilterParams computes the loop filter parameters, as specified in
-// section 15.4.
-func (d *Decoder) computeFilterParams() {
-	for i := range d.filterParams {
-		baseLevel := d.filterHeader.level
-		if d.segmentHeader.useSegment {
-			baseLevel = d.segmentHeader.filterStrength[i]
-			if d.segmentHeader.relativeDelta {
-				baseLevel += d.filterHeader.level
-			}
-		}
-
-		for j := range d.filterParams[i] {
-			p := &d.filterParams[i][j]
-			p.inner = j != 0
-			level := baseLevel
-			if d.filterHeader.useLFDelta {
-				// The libwebp C code has a "TODO: only CURRENT is handled for now."
-				level += d.filterHeader.refLFDelta[0]
-				if j != 0 {
-					level += d.filterHeader.modeLFDelta[0]
-				}
-			}
-			if level <= 0 {
-				p.level = 0
-				continue
-			}
-			if level > 63 {
-				level = 63
-			}
-			ilevel := level
-			if d.filterHeader.sharpness > 0 {
-				if d.filterHeader.sharpness > 4 {
-					ilevel >>= 2
-				} else {
-					ilevel >>= 1
-				}
-				if x := int8(9 - d.filterHeader.sharpness); ilevel > x {
-					ilevel = x
-				}
-			}
-			if ilevel < 1 {
-				ilevel = 1
-			}
-			p.ilevel = uint8(ilevel)
-			p.level = uint8(2*level + ilevel)
-			if d.frameHeader.KeyFrame {
-				if level < 15 {
-					p.hlevel = 0
-				} else if level < 40 {
-					p.hlevel = 1
-				} else {
-					p.hlevel = 2
-				}
-			} else {
-				if level < 15 {
-					p.hlevel = 0
-				} else if level < 20 {
-					p.hlevel = 1
-				} else if level < 40 {
-					p.hlevel = 2
-				} else {
-					p.hlevel = 3
-				}
-			}
-		}
-	}
-}
-
-// intSize is either 32 or 64.
-const intSize = 32 << (^uint(0) >> 63)
-
-func abs(x int) int {
-	// m := -1 if x < 0. m := 0 otherwise.
-	m := x >> (intSize - 1)
-
-	// In two's complement representation, the negative number
-	// of any number (except the smallest one) can be computed
-	// by flipping all the bits and add 1. This is faster than
-	// code with a branch.
-	// See Hacker's Delight, section 2-4.
-	return (x ^ m) - m
-}
-
-func clamp15(x int) int {
-	if x < -16 {
-		return -16
-	}
-	if x > 15 {
-		return 15
-	}
-	return x
-}
-
-func clamp127(x int) int {
-	if x < -128 {
-		return -128
-	}
-	if x > 127 {
-		return 127
-	}
-	return x
-}
-
-func clamp255(x int) uint8 {
-	if x < 0 {
-		return 0
-	}
-	if x > 255 {
-		return 255
-	}
-	return uint8(x)
-}
diff --git a/vendor/golang.org/x/image/vp8/idct.go b/vendor/golang.org/x/image/vp8/idct.go
deleted file mode 100644
index 929af2cc9..000000000
--- a/vendor/golang.org/x/image/vp8/idct.go
+++ /dev/null
@@ -1,98 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package vp8
-
-// This file implements the inverse Discrete Cosine Transform and the inverse
-// Walsh Hadamard Transform (WHT), as specified in sections 14.3 and 14.4.
-
-func clip8(i int32) uint8 {
-	if i < 0 {
-		return 0
-	}
-	if i > 255 {
-		return 255
-	}
-	return uint8(i)
-}
-
-func (z *Decoder) inverseDCT4(y, x, coeffBase int) {
-	const (
-		c1 = 85627 // 65536 * cos(pi/8) * sqrt(2).
-		c2 = 35468 // 65536 * sin(pi/8) * sqrt(2).
-	)
-	var m [4][4]int32
-	for i := 0; i < 4; i++ {
-		a := int32(z.coeff[coeffBase+0]) + int32(z.coeff[coeffBase+8])
-		b := int32(z.coeff[coeffBase+0]) - int32(z.coeff[coeffBase+8])
-		c := (int32(z.coeff[coeffBase+4])*c2)>>16 - (int32(z.coeff[coeffBase+12])*c1)>>16
-		d := (int32(z.coeff[coeffBase+4])*c1)>>16 + (int32(z.coeff[coeffBase+12])*c2)>>16
-		m[i][0] = a + d
-		m[i][1] = b + c
-		m[i][2] = b - c
-		m[i][3] = a - d
-		coeffBase++
-	}
-	for j := 0; j < 4; j++ {
-		dc := m[0][j] + 4
-		a := dc + m[2][j]
-		b := dc - m[2][j]
-		c := (m[1][j]*c2)>>16 - (m[3][j]*c1)>>16
-		d := (m[1][j]*c1)>>16 + (m[3][j]*c2)>>16
-		z.ybr[y+j][x+0] = clip8(int32(z.ybr[y+j][x+0]) + (a+d)>>3)
-		z.ybr[y+j][x+1] = clip8(int32(z.ybr[y+j][x+1]) + (b+c)>>3)
-		z.ybr[y+j][x+2] = clip8(int32(z.ybr[y+j][x+2]) + (b-c)>>3)
-		z.ybr[y+j][x+3] = clip8(int32(z.ybr[y+j][x+3]) + (a-d)>>3)
-	}
-}
-
-func (z *Decoder) inverseDCT4DCOnly(y, x, coeffBase int) {
-	dc := (int32(z.coeff[coeffBase+0]) + 4) >> 3
-	for j := 0; j < 4; j++ {
-		for i := 0; i < 4; i++ {
-			z.ybr[y+j][x+i] = clip8(int32(z.ybr[y+j][x+i]) + dc)
-		}
-	}
-}
-
-func (z *Decoder) inverseDCT8(y, x, coeffBase int) {
-	z.inverseDCT4(y+0, x+0, coeffBase+0*16)
-	z.inverseDCT4(y+0, x+4, coeffBase+1*16)
-	z.inverseDCT4(y+4, x+0, coeffBase+2*16)
-	z.inverseDCT4(y+4, x+4, coeffBase+3*16)
-}
-
-func (z *Decoder) inverseDCT8DCOnly(y, x, coeffBase int) {
-	z.inverseDCT4DCOnly(y+0, x+0, coeffBase+0*16)
-	z.inverseDCT4DCOnly(y+0, x+4, coeffBase+1*16)
-	z.inverseDCT4DCOnly(y+4, x+0, coeffBase+2*16)
-	z.inverseDCT4DCOnly(y+4, x+4, coeffBase+3*16)
-}
-
-func (d *Decoder) inverseWHT16() {
-	var m [16]int32
-	for i := 0; i < 4; i++ {
-		a0 := int32(d.coeff[384+0+i]) + int32(d.coeff[384+12+i])
-		a1 := int32(d.coeff[384+4+i]) + int32(d.coeff[384+8+i])
-		a2 := int32(d.coeff[384+4+i]) - int32(d.coeff[384+8+i])
-		a3 := int32(d.coeff[384+0+i]) - int32(d.coeff[384+12+i])
-		m[0+i] = a0 + a1
-		m[8+i] = a0 - a1
-		m[4+i] = a3 + a2
-		m[12+i] = a3 - a2
-	}
-	out := 0
-	for i := 0; i < 4; i++ {
-		dc := m[0+i*4] + 3
-		a0 := dc + m[3+i*4]
-		a1 := m[1+i*4] + m[2+i*4]
-		a2 := m[1+i*4] - m[2+i*4]
-		a3 := dc - m[3+i*4]
-		d.coeff[out+0] = int16((a0 + a1) >> 3)
-		d.coeff[out+16] = int16((a3 + a2) >> 3)
-		d.coeff[out+32] = int16((a0 - a1) >> 3)
-		d.coeff[out+48] = int16((a3 - a2) >> 3)
-		out += 64
-	}
-}
diff --git a/vendor/golang.org/x/image/vp8/partition.go b/vendor/golang.org/x/image/vp8/partition.go
deleted file mode 100644
index 72288bdeb..000000000
--- a/vendor/golang.org/x/image/vp8/partition.go
+++ /dev/null
@@ -1,129 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package vp8
-
-// Each VP8 frame consists of between 2 and 9 bitstream partitions.
-// Each partition is byte-aligned and is independently arithmetic-encoded.
-//
-// This file implements decoding a partition's bitstream, as specified in
-// chapter 7. The implementation follows libwebp's approach instead of the
-// specification's reference C implementation. For example, we use a look-up
-// table instead of a for loop to recalibrate the encoded range.
-
-var (
-	lutShift = [127]uint8{
-		7, 6, 6, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4,
-		3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,
-		2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
-		2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-		1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
-	}
-	lutRangeM1 = [127]uint8{
-		127,
-		127, 191,
-		127, 159, 191, 223,
-		127, 143, 159, 175, 191, 207, 223, 239,
-		127, 135, 143, 151, 159, 167, 175, 183, 191, 199, 207, 215, 223, 231, 239, 247,
-		127, 131, 135, 139, 143, 147, 151, 155, 159, 163, 167, 171, 175, 179, 183, 187,
-		191, 195, 199, 203, 207, 211, 215, 219, 223, 227, 231, 235, 239, 243, 247, 251,
-		127, 129, 131, 133, 135, 137, 139, 141, 143, 145, 147, 149, 151, 153, 155, 157,
-		159, 161, 163, 165, 167, 169, 171, 173, 175, 177, 179, 181, 183, 185, 187, 189,
-		191, 193, 195, 197, 199, 201, 203, 205, 207, 209, 211, 213, 215, 217, 219, 221,
-		223, 225, 227, 229, 231, 233, 235, 237, 239, 241, 243, 245, 247, 249, 251, 253,
-	}
-)
-
-// uniformProb represents a 50% probability that the next bit is 0.
-const uniformProb = 128
-
-// partition holds arithmetic-coded bits.
-type partition struct {
-	// buf is the input bytes.
-	buf []byte
-	// r is how many of buf's bytes have been consumed.
-	r int
-	// rangeM1 is range minus 1, where range is in the arithmetic coding sense,
-	// not the Go language sense.
-	rangeM1 uint32
-	// bits and nBits hold those bits shifted out of buf but not yet consumed.
-	bits  uint32
-	nBits uint8
-	// unexpectedEOF tells whether we tried to read past buf.
-	unexpectedEOF bool
-}
-
-// init initializes the partition.
-func (p *partition) init(buf []byte) {
-	p.buf = buf
-	p.r = 0
-	p.rangeM1 = 254
-	p.bits = 0
-	p.nBits = 0
-	p.unexpectedEOF = false
-}
-
-// readBit returns the next bit.
-func (p *partition) readBit(prob uint8) bool {
-	if p.nBits < 8 {
-		if p.r >= len(p.buf) {
-			p.unexpectedEOF = true
-			return false
-		}
-		// Expression split for 386 compiler.
-		x := uint32(p.buf[p.r])
-		p.bits |= x << (8 - p.nBits)
-		p.r++
-		p.nBits += 8
-	}
-	split := (p.rangeM1*uint32(prob))>>8 + 1
-	bit := p.bits >= split<<8
-	if bit {
-		p.rangeM1 -= split
-		p.bits -= split << 8
-	} else {
-		p.rangeM1 = split - 1
-	}
-	if p.rangeM1 < 127 {
-		shift := lutShift[p.rangeM1]
-		p.rangeM1 = uint32(lutRangeM1[p.rangeM1])
-		p.bits <<= shift
-		p.nBits -= shift
-	}
-	return bit
-}
-
-// readUint returns the next n-bit unsigned integer.
-func (p *partition) readUint(prob, n uint8) uint32 {
-	var u uint32
-	for n > 0 {
-		n--
-		if p.readBit(prob) {
-			u |= 1 << n
-		}
-	}
-	return u
-}
-
-// readInt returns the next n-bit signed integer.
-func (p *partition) readInt(prob, n uint8) int32 {
-	u := p.readUint(prob, n)
-	b := p.readBit(prob)
-	if b {
-		return -int32(u)
-	}
-	return int32(u)
-}
-
-// readOptionalInt returns the next n-bit signed integer in an encoding
-// where the likely result is zero.
-func (p *partition) readOptionalInt(prob, n uint8) int32 {
-	if !p.readBit(prob) {
-		return 0
-	}
-	return p.readInt(prob, n)
-}
diff --git a/vendor/golang.org/x/image/vp8/pred.go b/vendor/golang.org/x/image/vp8/pred.go
deleted file mode 100644
index 58c2689ea..000000000
--- a/vendor/golang.org/x/image/vp8/pred.go
+++ /dev/null
@@ -1,201 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package vp8
-
-// This file implements parsing the predictor modes, as specified in chapter
-// 11.
-
-func (d *Decoder) parsePredModeY16(mbx int) {
-	var p uint8
-	if !d.fp.readBit(156) {
-		if !d.fp.readBit(163) {
-			p = predDC
-		} else {
-			p = predVE
-		}
-	} else if !d.fp.readBit(128) {
-		p = predHE
-	} else {
-		p = predTM
-	}
-	for i := 0; i < 4; i++ {
-		d.upMB[mbx].pred[i] = p
-		d.leftMB.pred[i] = p
-	}
-	d.predY16 = p
-}
-
-func (d *Decoder) parsePredModeC8() {
-	if !d.fp.readBit(142) {
-		d.predC8 = predDC
-	} else if !d.fp.readBit(114) {
-		d.predC8 = predVE
-	} else if !d.fp.readBit(183) {
-		d.predC8 = predHE
-	} else {
-		d.predC8 = predTM
-	}
-}
-
-func (d *Decoder) parsePredModeY4(mbx int) {
-	for j := 0; j < 4; j++ {
-		p := d.leftMB.pred[j]
-		for i := 0; i < 4; i++ {
-			prob := &predProb[d.upMB[mbx].pred[i]][p]
-			if !d.fp.readBit(prob[0]) {
-				p = predDC
-			} else if !d.fp.readBit(prob[1]) {
-				p = predTM
-			} else if !d.fp.readBit(prob[2]) {
-				p = predVE
-			} else if !d.fp.readBit(prob[3]) {
-				if !d.fp.readBit(prob[4]) {
-					p = predHE
-				} else if !d.fp.readBit(prob[5]) {
-					p = predRD
-				} else {
-					p = predVR
-				}
-			} else if !d.fp.readBit(prob[6]) {
-				p = predLD
-			} else if !d.fp.readBit(prob[7]) {
-				p = predVL
-			} else if !d.fp.readBit(prob[8]) {
-				p = predHD
-			} else {
-				p = predHU
-			}
-			d.predY4[j][i] = p
-			d.upMB[mbx].pred[i] = p
-		}
-		d.leftMB.pred[j] = p
-	}
-}
-
-// predProb are the probabilities to decode a 4x4 region's predictor mode given
-// the predictor modes of the regions above and left of it.
-// These values are specified in section 11.5.
-var predProb = [nPred][nPred][9]uint8{
-	{
-		{231, 120, 48, 89, 115, 113, 120, 152, 112},
-		{152, 179, 64, 126, 170, 118, 46, 70, 95},
-		{175, 69, 143, 80, 85, 82, 72, 155, 103},
-		{56, 58, 10, 171, 218, 189, 17, 13, 152},
-		{114, 26, 17, 163, 44, 195, 21, 10, 173},
-		{121, 24, 80, 195, 26, 62, 44, 64, 85},
-		{144, 71, 10, 38, 171, 213, 144, 34, 26},
-		{170, 46, 55, 19, 136, 160, 33, 206, 71},
-		{63, 20, 8, 114, 114, 208, 12, 9, 226},
-		{81, 40, 11, 96, 182, 84, 29, 16, 36},
-	},
-	{
-		{134, 183, 89, 137, 98, 101, 106, 165, 148},
-		{72, 187, 100, 130, 157, 111, 32, 75, 80},
-		{66, 102, 167, 99, 74, 62, 40, 234, 128},
-		{41, 53, 9, 178, 241, 141, 26, 8, 107},
-		{74, 43, 26, 146, 73, 166, 49, 23, 157},
-		{65, 38, 105, 160, 51, 52, 31, 115, 128},
-		{104, 79, 12, 27, 217, 255, 87, 17, 7},
-		{87, 68, 71, 44, 114, 51, 15, 186, 23},
-		{47, 41, 14, 110, 182, 183, 21, 17, 194},
-		{66, 45, 25, 102, 197, 189, 23, 18, 22},
-	},
-	{
-		{88, 88, 147, 150, 42, 46, 45, 196, 205},
-		{43, 97, 183, 117, 85, 38, 35, 179, 61},
-		{39, 53, 200, 87, 26, 21, 43, 232, 171},
-		{56, 34, 51, 104, 114, 102, 29, 93, 77},
-		{39, 28, 85, 171, 58, 165, 90, 98, 64},
-		{34, 22, 116, 206, 23, 34, 43, 166, 73},
-		{107, 54, 32, 26, 51, 1, 81, 43, 31},
-		{68, 25, 106, 22, 64, 171, 36, 225, 114},
-		{34, 19, 21, 102, 132, 188, 16, 76, 124},
-		{62, 18, 78, 95, 85, 57, 50, 48, 51},
-	},
-	{
-		{193, 101, 35, 159, 215, 111, 89, 46, 111},
-		{60, 148, 31, 172, 219, 228, 21, 18, 111},
-		{112, 113, 77, 85, 179, 255, 38, 120, 114},
-		{40, 42, 1, 196, 245, 209, 10, 25, 109},
-		{88, 43, 29, 140, 166, 213, 37, 43, 154},
-		{61, 63, 30, 155, 67, 45, 68, 1, 209},
-		{100, 80, 8, 43, 154, 1, 51, 26, 71},
-		{142, 78, 78, 16, 255, 128, 34, 197, 171},
-		{41, 40, 5, 102, 211, 183, 4, 1, 221},
-		{51, 50, 17, 168, 209, 192, 23, 25, 82},
-	},
-	{
-		{138, 31, 36, 171, 27, 166, 38, 44, 229},
-		{67, 87, 58, 169, 82, 115, 26, 59, 179},
-		{63, 59, 90, 180, 59, 166, 93, 73, 154},
-		{40, 40, 21, 116, 143, 209, 34, 39, 175},
-		{47, 15, 16, 183, 34, 223, 49, 45, 183},
-		{46, 17, 33, 183, 6, 98, 15, 32, 183},
-		{57, 46, 22, 24, 128, 1, 54, 17, 37},
-		{65, 32, 73, 115, 28, 128, 23, 128, 205},
-		{40, 3, 9, 115, 51, 192, 18, 6, 223},
-		{87, 37, 9, 115, 59, 77, 64, 21, 47},
-	},
-	{
-		{104, 55, 44, 218, 9, 54, 53, 130, 226},
-		{64, 90, 70, 205, 40, 41, 23, 26, 57},
-		{54, 57, 112, 184, 5, 41, 38, 166, 213},
-		{30, 34, 26, 133, 152, 116, 10, 32, 134},
-		{39, 19, 53, 221, 26, 114, 32, 73, 255},
-		{31, 9, 65, 234, 2, 15, 1, 118, 73},
-		{75, 32, 12, 51, 192, 255, 160, 43, 51},
-		{88, 31, 35, 67, 102, 85, 55, 186, 85},
-		{56, 21, 23, 111, 59, 205, 45, 37, 192},
-		{55, 38, 70, 124, 73, 102, 1, 34, 98},
-	},
-	{
-		{125, 98, 42, 88, 104, 85, 117, 175, 82},
-		{95, 84, 53, 89, 128, 100, 113, 101, 45},
-		{75, 79, 123, 47, 51, 128, 81, 171, 1},
-		{57, 17, 5, 71, 102, 57, 53, 41, 49},
-		{38, 33, 13, 121, 57, 73, 26, 1, 85},
-		{41, 10, 67, 138, 77, 110, 90, 47, 114},
-		{115, 21, 2, 10, 102, 255, 166, 23, 6},
-		{101, 29, 16, 10, 85, 128, 101, 196, 26},
-		{57, 18, 10, 102, 102, 213, 34, 20, 43},
-		{117, 20, 15, 36, 163, 128, 68, 1, 26},
-	},
-	{
-		{102, 61, 71, 37, 34, 53, 31, 243, 192},
-		{69, 60, 71, 38, 73, 119, 28, 222, 37},
-		{68, 45, 128, 34, 1, 47, 11, 245, 171},
-		{62, 17, 19, 70, 146, 85, 55, 62, 70},
-		{37, 43, 37, 154, 100, 163, 85, 160, 1},
-		{63, 9, 92, 136, 28, 64, 32, 201, 85},
-		{75, 15, 9, 9, 64, 255, 184, 119, 16},
-		{86, 6, 28, 5, 64, 255, 25, 248, 1},
-		{56, 8, 17, 132, 137, 255, 55, 116, 128},
-		{58, 15, 20, 82, 135, 57, 26, 121, 40},
-	},
-	{
-		{164, 50, 31, 137, 154, 133, 25, 35, 218},
-		{51, 103, 44, 131, 131, 123, 31, 6, 158},
-		{86, 40, 64, 135, 148, 224, 45, 183, 128},
-		{22, 26, 17, 131, 240, 154, 14, 1, 209},
-		{45, 16, 21, 91, 64, 222, 7, 1, 197},
-		{56, 21, 39, 155, 60, 138, 23, 102, 213},
-		{83, 12, 13, 54, 192, 255, 68, 47, 28},
-		{85, 26, 85, 85, 128, 128, 32, 146, 171},
-		{18, 11, 7, 63, 144, 171, 4, 4, 246},
-		{35, 27, 10, 146, 174, 171, 12, 26, 128},
-	},
-	{
-		{190, 80, 35, 99, 180, 80, 126, 54, 45},
-		{85, 126, 47, 87, 176, 51, 41, 20, 32},
-		{101, 75, 128, 139, 118, 146, 116, 128, 85},
-		{56, 41, 15, 176, 236, 85, 37, 9, 62},
-		{71, 30, 17, 119, 118, 255, 17, 18, 138},
-		{101, 38, 60, 138, 55, 70, 43, 26, 142},
-		{146, 36, 19, 30, 171, 255, 97, 27, 20},
-		{138, 45, 61, 62, 219, 1, 81, 188, 64},
-		{32, 41, 20, 117, 151, 142, 20, 21, 163},
-		{112, 19, 12, 61, 195, 128, 48, 4, 24},
-	},
-}
diff --git a/vendor/golang.org/x/image/vp8/predfunc.go b/vendor/golang.org/x/image/vp8/predfunc.go
deleted file mode 100644
index f8999582b..000000000
--- a/vendor/golang.org/x/image/vp8/predfunc.go
+++ /dev/null
@@ -1,553 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package vp8
-
-// This file implements the predicition functions, as specified in chapter 12.
-//
-// For each macroblock (of 1x16x16 luma and 2x8x8 chroma coefficients), the
-// luma values are either predicted as one large 16x16 region or 16 separate
-// 4x4 regions. The chroma values are always predicted as one 8x8 region.
-//
-// For 4x4 regions, the target block's predicted values (Xs) are a function of
-// its previously-decoded top and left border values, as well as a number of
-// pixels from the top-right:
-//
-//	a b c d e f g h
-//	p X X X X
-//	q X X X X
-//	r X X X X
-//	s X X X X
-//
-// The predictor modes are:
-//	- DC: all Xs = (b + c + d + e + p + q + r + s + 4) / 8.
-//	- TM: the first X = (b + p - a), the second X = (c + p - a), and so on.
-//	- VE: each X = the weighted average of its column's top value and that
-//	      value's neighbors, i.e. averages of abc, bcd, cde or def.
-//	- HE: similar to VE except rows instead of columns, and the final row is
-//	      an average of r, s and s.
-//	- RD, VR, LD, VL, HD, HU: these diagonal modes ("Right Down", "Vertical
-//	      Right", etc) are more complicated and are described in section 12.3.
-// All Xs are clipped to the range [0, 255].
-//
-// For 8x8 and 16x16 regions, the target block's predicted values are a
-// function of the top and left border values without the top-right overhang,
-// i.e. without the 8x8 or 16x16 equivalent of f, g and h. Furthermore:
-//	- There are no diagonal predictor modes, only DC, TM, VE and HE.
-//	- The DC mode has variants for macroblocks in the top row and/or left
-//	  column, i.e. for macroblocks with mby == 0 || mbx == 0.
-//	- The VE and HE modes take only the column top or row left values; they do
-//	  not smooth that top/left value with its neighbors.
-
-// nPred is the number of predictor modes, not including the Top/Left versions
-// of the DC predictor mode.
-const nPred = 10
-
-const (
-	predDC = iota
-	predTM
-	predVE
-	predHE
-	predRD
-	predVR
-	predLD
-	predVL
-	predHD
-	predHU
-	predDCTop
-	predDCLeft
-	predDCTopLeft
-)
-
-func checkTopLeftPred(mbx, mby int, p uint8) uint8 {
-	if p != predDC {
-		return p
-	}
-	if mbx == 0 {
-		if mby == 0 {
-			return predDCTopLeft
-		}
-		return predDCLeft
-	}
-	if mby == 0 {
-		return predDCTop
-	}
-	return predDC
-}
-
-var predFunc4 = [...]func(*Decoder, int, int){
-	predFunc4DC,
-	predFunc4TM,
-	predFunc4VE,
-	predFunc4HE,
-	predFunc4RD,
-	predFunc4VR,
-	predFunc4LD,
-	predFunc4VL,
-	predFunc4HD,
-	predFunc4HU,
-	nil,
-	nil,
-	nil,
-}
-
-var predFunc8 = [...]func(*Decoder, int, int){
-	predFunc8DC,
-	predFunc8TM,
-	predFunc8VE,
-	predFunc8HE,
-	nil,
-	nil,
-	nil,
-	nil,
-	nil,
-	nil,
-	predFunc8DCTop,
-	predFunc8DCLeft,
-	predFunc8DCTopLeft,
-}
-
-var predFunc16 = [...]func(*Decoder, int, int){
-	predFunc16DC,
-	predFunc16TM,
-	predFunc16VE,
-	predFunc16HE,
-	nil,
-	nil,
-	nil,
-	nil,
-	nil,
-	nil,
-	predFunc16DCTop,
-	predFunc16DCLeft,
-	predFunc16DCTopLeft,
-}
-
-func predFunc4DC(z *Decoder, y, x int) {
-	sum := uint32(4)
-	for i := 0; i < 4; i++ {
-		sum += uint32(z.ybr[y-1][x+i])
-	}
-	for j := 0; j < 4; j++ {
-		sum += uint32(z.ybr[y+j][x-1])
-	}
-	avg := uint8(sum / 8)
-	for j := 0; j < 4; j++ {
-		for i := 0; i < 4; i++ {
-			z.ybr[y+j][x+i] = avg
-		}
-	}
-}
-
-func predFunc4TM(z *Decoder, y, x int) {
-	delta0 := -int32(z.ybr[y-1][x-1])
-	for j := 0; j < 4; j++ {
-		delta1 := delta0 + int32(z.ybr[y+j][x-1])
-		for i := 0; i < 4; i++ {
-			delta2 := delta1 + int32(z.ybr[y-1][x+i])
-			z.ybr[y+j][x+i] = uint8(clip(delta2, 0, 255))
-		}
-	}
-}
-
-func predFunc4VE(z *Decoder, y, x int) {
-	a := int32(z.ybr[y-1][x-1])
-	b := int32(z.ybr[y-1][x+0])
-	c := int32(z.ybr[y-1][x+1])
-	d := int32(z.ybr[y-1][x+2])
-	e := int32(z.ybr[y-1][x+3])
-	f := int32(z.ybr[y-1][x+4])
-	abc := uint8((a + 2*b + c + 2) / 4)
-	bcd := uint8((b + 2*c + d + 2) / 4)
-	cde := uint8((c + 2*d + e + 2) / 4)
-	def := uint8((d + 2*e + f + 2) / 4)
-	for j := 0; j < 4; j++ {
-		z.ybr[y+j][x+0] = abc
-		z.ybr[y+j][x+1] = bcd
-		z.ybr[y+j][x+2] = cde
-		z.ybr[y+j][x+3] = def
-	}
-}
-
-func predFunc4HE(z *Decoder, y, x int) {
-	s := int32(z.ybr[y+3][x-1])
-	r := int32(z.ybr[y+2][x-1])
-	q := int32(z.ybr[y+1][x-1])
-	p := int32(z.ybr[y+0][x-1])
-	a := int32(z.ybr[y-1][x-1])
-	ssr := uint8((s + 2*s + r + 2) / 4)
-	srq := uint8((s + 2*r + q + 2) / 4)
-	rqp := uint8((r + 2*q + p + 2) / 4)
-	apq := uint8((a + 2*p + q + 2) / 4)
-	for i := 0; i < 4; i++ {
-		z.ybr[y+0][x+i] = apq
-		z.ybr[y+1][x+i] = rqp
-		z.ybr[y+2][x+i] = srq
-		z.ybr[y+3][x+i] = ssr
-	}
-}
-
-func predFunc4RD(z *Decoder, y, x int) {
-	s := int32(z.ybr[y+3][x-1])
-	r := int32(z.ybr[y+2][x-1])
-	q := int32(z.ybr[y+1][x-1])
-	p := int32(z.ybr[y+0][x-1])
-	a := int32(z.ybr[y-1][x-1])
-	b := int32(z.ybr[y-1][x+0])
-	c := int32(z.ybr[y-1][x+1])
-	d := int32(z.ybr[y-1][x+2])
-	e := int32(z.ybr[y-1][x+3])
-	srq := uint8((s + 2*r + q + 2) / 4)
-	rqp := uint8((r + 2*q + p + 2) / 4)
-	qpa := uint8((q + 2*p + a + 2) / 4)
-	pab := uint8((p + 2*a + b + 2) / 4)
-	abc := uint8((a + 2*b + c + 2) / 4)
-	bcd := uint8((b + 2*c + d + 2) / 4)
-	cde := uint8((c + 2*d + e + 2) / 4)
-	z.ybr[y+0][x+0] = pab
-	z.ybr[y+0][x+1] = abc
-	z.ybr[y+0][x+2] = bcd
-	z.ybr[y+0][x+3] = cde
-	z.ybr[y+1][x+0] = qpa
-	z.ybr[y+1][x+1] = pab
-	z.ybr[y+1][x+2] = abc
-	z.ybr[y+1][x+3] = bcd
-	z.ybr[y+2][x+0] = rqp
-	z.ybr[y+2][x+1] = qpa
-	z.ybr[y+2][x+2] = pab
-	z.ybr[y+2][x+3] = abc
-	z.ybr[y+3][x+0] = srq
-	z.ybr[y+3][x+1] = rqp
-	z.ybr[y+3][x+2] = qpa
-	z.ybr[y+3][x+3] = pab
-}
-
-func predFunc4VR(z *Decoder, y, x int) {
-	r := int32(z.ybr[y+2][x-1])
-	q := int32(z.ybr[y+1][x-1])
-	p := int32(z.ybr[y+0][x-1])
-	a := int32(z.ybr[y-1][x-1])
-	b := int32(z.ybr[y-1][x+0])
-	c := int32(z.ybr[y-1][x+1])
-	d := int32(z.ybr[y-1][x+2])
-	e := int32(z.ybr[y-1][x+3])
-	ab := uint8((a + b + 1) / 2)
-	bc := uint8((b + c + 1) / 2)
-	cd := uint8((c + d + 1) / 2)
-	de := uint8((d + e + 1) / 2)
-	rqp := uint8((r + 2*q + p + 2) / 4)
-	qpa := uint8((q + 2*p + a + 2) / 4)
-	pab := uint8((p + 2*a + b + 2) / 4)
-	abc := uint8((a + 2*b + c + 2) / 4)
-	bcd := uint8((b + 2*c + d + 2) / 4)
-	cde := uint8((c + 2*d + e + 2) / 4)
-	z.ybr[y+0][x+0] = ab
-	z.ybr[y+0][x+1] = bc
-	z.ybr[y+0][x+2] = cd
-	z.ybr[y+0][x+3] = de
-	z.ybr[y+1][x+0] = pab
-	z.ybr[y+1][x+1] = abc
-	z.ybr[y+1][x+2] = bcd
-	z.ybr[y+1][x+3] = cde
-	z.ybr[y+2][x+0] = qpa
-	z.ybr[y+2][x+1] = ab
-	z.ybr[y+2][x+2] = bc
-	z.ybr[y+2][x+3] = cd
-	z.ybr[y+3][x+0] = rqp
-	z.ybr[y+3][x+1] = pab
-	z.ybr[y+3][x+2] = abc
-	z.ybr[y+3][x+3] = bcd
-}
-
-func predFunc4LD(z *Decoder, y, x int) {
-	a := int32(z.ybr[y-1][x+0])
-	b := int32(z.ybr[y-1][x+1])
-	c := int32(z.ybr[y-1][x+2])
-	d := int32(z.ybr[y-1][x+3])
-	e := int32(z.ybr[y-1][x+4])
-	f := int32(z.ybr[y-1][x+5])
-	g := int32(z.ybr[y-1][x+6])
-	h := int32(z.ybr[y-1][x+7])
-	abc := uint8((a + 2*b + c + 2) / 4)
-	bcd := uint8((b + 2*c + d + 2) / 4)
-	cde := uint8((c + 2*d + e + 2) / 4)
-	def := uint8((d + 2*e + f + 2) / 4)
-	efg := uint8((e + 2*f + g + 2) / 4)
-	fgh := uint8((f + 2*g + h + 2) / 4)
-	ghh := uint8((g + 2*h + h + 2) / 4)
-	z.ybr[y+0][x+0] = abc
-	z.ybr[y+0][x+1] = bcd
-	z.ybr[y+0][x+2] = cde
-	z.ybr[y+0][x+3] = def
-	z.ybr[y+1][x+0] = bcd
-	z.ybr[y+1][x+1] = cde
-	z.ybr[y+1][x+2] = def
-	z.ybr[y+1][x+3] = efg
-	z.ybr[y+2][x+0] = cde
-	z.ybr[y+2][x+1] = def
-	z.ybr[y+2][x+2] = efg
-	z.ybr[y+2][x+3] = fgh
-	z.ybr[y+3][x+0] = def
-	z.ybr[y+3][x+1] = efg
-	z.ybr[y+3][x+2] = fgh
-	z.ybr[y+3][x+3] = ghh
-}
-
-func predFunc4VL(z *Decoder, y, x int) {
-	a := int32(z.ybr[y-1][x+0])
-	b := int32(z.ybr[y-1][x+1])
-	c := int32(z.ybr[y-1][x+2])
-	d := int32(z.ybr[y-1][x+3])
-	e := int32(z.ybr[y-1][x+4])
-	f := int32(z.ybr[y-1][x+5])
-	g := int32(z.ybr[y-1][x+6])
-	h := int32(z.ybr[y-1][x+7])
-	ab := uint8((a + b + 1) / 2)
-	bc := uint8((b + c + 1) / 2)
-	cd := uint8((c + d + 1) / 2)
-	de := uint8((d + e + 1) / 2)
-	abc := uint8((a + 2*b + c + 2) / 4)
-	bcd := uint8((b + 2*c + d + 2) / 4)
-	cde := uint8((c + 2*d + e + 2) / 4)
-	def := uint8((d + 2*e + f + 2) / 4)
-	efg := uint8((e + 2*f + g + 2) / 4)
-	fgh := uint8((f + 2*g + h + 2) / 4)
-	z.ybr[y+0][x+0] = ab
-	z.ybr[y+0][x+1] = bc
-	z.ybr[y+0][x+2] = cd
-	z.ybr[y+0][x+3] = de
-	z.ybr[y+1][x+0] = abc
-	z.ybr[y+1][x+1] = bcd
-	z.ybr[y+1][x+2] = cde
-	z.ybr[y+1][x+3] = def
-	z.ybr[y+2][x+0] = bc
-	z.ybr[y+2][x+1] = cd
-	z.ybr[y+2][x+2] = de
-	z.ybr[y+2][x+3] = efg
-	z.ybr[y+3][x+0] = bcd
-	z.ybr[y+3][x+1] = cde
-	z.ybr[y+3][x+2] = def
-	z.ybr[y+3][x+3] = fgh
-}
-
-func predFunc4HD(z *Decoder, y, x int) {
-	s := int32(z.ybr[y+3][x-1])
-	r := int32(z.ybr[y+2][x-1])
-	q := int32(z.ybr[y+1][x-1])
-	p := int32(z.ybr[y+0][x-1])
-	a := int32(z.ybr[y-1][x-1])
-	b := int32(z.ybr[y-1][x+0])
-	c := int32(z.ybr[y-1][x+1])
-	d := int32(z.ybr[y-1][x+2])
-	sr := uint8((s + r + 1) / 2)
-	rq := uint8((r + q + 1) / 2)
-	qp := uint8((q + p + 1) / 2)
-	pa := uint8((p + a + 1) / 2)
-	srq := uint8((s + 2*r + q + 2) / 4)
-	rqp := uint8((r + 2*q + p + 2) / 4)
-	qpa := uint8((q + 2*p + a + 2) / 4)
-	pab := uint8((p + 2*a + b + 2) / 4)
-	abc := uint8((a + 2*b + c + 2) / 4)
-	bcd := uint8((b + 2*c + d + 2) / 4)
-	z.ybr[y+0][x+0] = pa
-	z.ybr[y+0][x+1] = pab
-	z.ybr[y+0][x+2] = abc
-	z.ybr[y+0][x+3] = bcd
-	z.ybr[y+1][x+0] = qp
-	z.ybr[y+1][x+1] = qpa
-	z.ybr[y+1][x+2] = pa
-	z.ybr[y+1][x+3] = pab
-	z.ybr[y+2][x+0] = rq
-	z.ybr[y+2][x+1] = rqp
-	z.ybr[y+2][x+2] = qp
-	z.ybr[y+2][x+3] = qpa
-	z.ybr[y+3][x+0] = sr
-	z.ybr[y+3][x+1] = srq
-	z.ybr[y+3][x+2] = rq
-	z.ybr[y+3][x+3] = rqp
-}
-
-func predFunc4HU(z *Decoder, y, x int) {
-	s := int32(z.ybr[y+3][x-1])
-	r := int32(z.ybr[y+2][x-1])
-	q := int32(z.ybr[y+1][x-1])
-	p := int32(z.ybr[y+0][x-1])
-	pq := uint8((p + q + 1) / 2)
-	qr := uint8((q + r + 1) / 2)
-	rs := uint8((r + s + 1) / 2)
-	pqr := uint8((p + 2*q + r + 2) / 4)
-	qrs := uint8((q + 2*r + s + 2) / 4)
-	rss := uint8((r + 2*s + s + 2) / 4)
-	sss := uint8(s)
-	z.ybr[y+0][x+0] = pq
-	z.ybr[y+0][x+1] = pqr
-	z.ybr[y+0][x+2] = qr
-	z.ybr[y+0][x+3] = qrs
-	z.ybr[y+1][x+0] = qr
-	z.ybr[y+1][x+1] = qrs
-	z.ybr[y+1][x+2] = rs
-	z.ybr[y+1][x+3] = rss
-	z.ybr[y+2][x+0] = rs
-	z.ybr[y+2][x+1] = rss
-	z.ybr[y+2][x+2] = sss
-	z.ybr[y+2][x+3] = sss
-	z.ybr[y+3][x+0] = sss
-	z.ybr[y+3][x+1] = sss
-	z.ybr[y+3][x+2] = sss
-	z.ybr[y+3][x+3] = sss
-}
-
-func predFunc8DC(z *Decoder, y, x int) {
-	sum := uint32(8)
-	for i := 0; i < 8; i++ {
-		sum += uint32(z.ybr[y-1][x+i])
-	}
-	for j := 0; j < 8; j++ {
-		sum += uint32(z.ybr[y+j][x-1])
-	}
-	avg := uint8(sum / 16)
-	for j := 0; j < 8; j++ {
-		for i := 0; i < 8; i++ {
-			z.ybr[y+j][x+i] = avg
-		}
-	}
-}
-
-func predFunc8TM(z *Decoder, y, x int) {
-	delta0 := -int32(z.ybr[y-1][x-1])
-	for j := 0; j < 8; j++ {
-		delta1 := delta0 + int32(z.ybr[y+j][x-1])
-		for i := 0; i < 8; i++ {
-			delta2 := delta1 + int32(z.ybr[y-1][x+i])
-			z.ybr[y+j][x+i] = uint8(clip(delta2, 0, 255))
-		}
-	}
-}
-
-func predFunc8VE(z *Decoder, y, x int) {
-	for j := 0; j < 8; j++ {
-		for i := 0; i < 8; i++ {
-			z.ybr[y+j][x+i] = z.ybr[y-1][x+i]
-		}
-	}
-}
-
-func predFunc8HE(z *Decoder, y, x int) {
-	for j := 0; j < 8; j++ {
-		for i := 0; i < 8; i++ {
-			z.ybr[y+j][x+i] = z.ybr[y+j][x-1]
-		}
-	}
-}
-
-func predFunc8DCTop(z *Decoder, y, x int) {
-	sum := uint32(4)
-	for j := 0; j < 8; j++ {
-		sum += uint32(z.ybr[y+j][x-1])
-	}
-	avg := uint8(sum / 8)
-	for j := 0; j < 8; j++ {
-		for i := 0; i < 8; i++ {
-			z.ybr[y+j][x+i] = avg
-		}
-	}
-}
-
-func predFunc8DCLeft(z *Decoder, y, x int) {
-	sum := uint32(4)
-	for i := 0; i < 8; i++ {
-		sum += uint32(z.ybr[y-1][x+i])
-	}
-	avg := uint8(sum / 8)
-	for j := 0; j < 8; j++ {
-		for i := 0; i < 8; i++ {
-			z.ybr[y+j][x+i] = avg
-		}
-	}
-}
-
-func predFunc8DCTopLeft(z *Decoder, y, x int) {
-	for j := 0; j < 8; j++ {
-		for i := 0; i < 8; i++ {
-			z.ybr[y+j][x+i] = 0x80
-		}
-	}
-}
-
-func predFunc16DC(z *Decoder, y, x int) {
-	sum := uint32(16)
-	for i := 0; i < 16; i++ {
-		sum += uint32(z.ybr[y-1][x+i])
-	}
-	for j := 0; j < 16; j++ {
-		sum += uint32(z.ybr[y+j][x-1])
-	}
-	avg := uint8(sum / 32)
-	for j := 0; j < 16; j++ {
-		for i := 0; i < 16; i++ {
-			z.ybr[y+j][x+i] = avg
-		}
-	}
-}
-
-func predFunc16TM(z *Decoder, y, x int) {
-	delta0 := -int32(z.ybr[y-1][x-1])
-	for j := 0; j < 16; j++ {
-		delta1 := delta0 + int32(z.ybr[y+j][x-1])
-		for i := 0; i < 16; i++ {
-			delta2 := delta1 + int32(z.ybr[y-1][x+i])
-			z.ybr[y+j][x+i] = uint8(clip(delta2, 0, 255))
-		}
-	}
-}
-
-func predFunc16VE(z *Decoder, y, x int) {
-	for j := 0; j < 16; j++ {
-		for i := 0; i < 16; i++ {
-			z.ybr[y+j][x+i] = z.ybr[y-1][x+i]
-		}
-	}
-}
-
-func predFunc16HE(z *Decoder, y, x int) {
-	for j := 0; j < 16; j++ {
-		for i := 0; i < 16; i++ {
-			z.ybr[y+j][x+i] = z.ybr[y+j][x-1]
-		}
-	}
-}
-
-func predFunc16DCTop(z *Decoder, y, x int) {
-	sum := uint32(8)
-	for j := 0; j < 16; j++ {
-		sum += uint32(z.ybr[y+j][x-1])
-	}
-	avg := uint8(sum / 16)
-	for j := 0; j < 16; j++ {
-		for i := 0; i < 16; i++ {
-			z.ybr[y+j][x+i] = avg
-		}
-	}
-}
-
-func predFunc16DCLeft(z *Decoder, y, x int) {
-	sum := uint32(8)
-	for i := 0; i < 16; i++ {
-		sum += uint32(z.ybr[y-1][x+i])
-	}
-	avg := uint8(sum / 16)
-	for j := 0; j < 16; j++ {
-		for i := 0; i < 16; i++ {
-			z.ybr[y+j][x+i] = avg
-		}
-	}
-}
-
-func predFunc16DCTopLeft(z *Decoder, y, x int) {
-	for j := 0; j < 16; j++ {
-		for i := 0; i < 16; i++ {
-			z.ybr[y+j][x+i] = 0x80
-		}
-	}
-}
diff --git a/vendor/golang.org/x/image/vp8/quant.go b/vendor/golang.org/x/image/vp8/quant.go
deleted file mode 100644
index da4361604..000000000
--- a/vendor/golang.org/x/image/vp8/quant.go
+++ /dev/null
@@ -1,98 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package vp8
-
-// This file implements parsing the quantization factors.
-
-// quant are DC/AC quantization factors.
-type quant struct {
-	y1 [2]uint16
-	y2 [2]uint16
-	uv [2]uint16
-}
-
-// clip clips x to the range [min, max] inclusive.
-func clip(x, min, max int32) int32 {
-	if x < min {
-		return min
-	}
-	if x > max {
-		return max
-	}
-	return x
-}
-
-// parseQuant parses the quantization factors, as specified in section 9.6.
-func (d *Decoder) parseQuant() {
-	baseQ0 := d.fp.readUint(uniformProb, 7)
-	dqy1DC := d.fp.readOptionalInt(uniformProb, 4)
-	const dqy1AC = 0
-	dqy2DC := d.fp.readOptionalInt(uniformProb, 4)
-	dqy2AC := d.fp.readOptionalInt(uniformProb, 4)
-	dquvDC := d.fp.readOptionalInt(uniformProb, 4)
-	dquvAC := d.fp.readOptionalInt(uniformProb, 4)
-	for i := 0; i < nSegment; i++ {
-		q := int32(baseQ0)
-		if d.segmentHeader.useSegment {
-			if d.segmentHeader.relativeDelta {
-				q += int32(d.segmentHeader.quantizer[i])
-			} else {
-				q = int32(d.segmentHeader.quantizer[i])
-			}
-		}
-		d.quant[i].y1[0] = dequantTableDC[clip(q+dqy1DC, 0, 127)]
-		d.quant[i].y1[1] = dequantTableAC[clip(q+dqy1AC, 0, 127)]
-		d.quant[i].y2[0] = dequantTableDC[clip(q+dqy2DC, 0, 127)] * 2
-		d.quant[i].y2[1] = dequantTableAC[clip(q+dqy2AC, 0, 127)] * 155 / 100
-		if d.quant[i].y2[1] < 8 {
-			d.quant[i].y2[1] = 8
-		}
-		// The 117 is not a typo. The dequant_init function in the spec's Reference
-		// Decoder Source Code (http://tools.ietf.org/html/rfc6386#section-9.6 Page 145)
-		// says to clamp the LHS value at 132, which is equal to dequantTableDC[117].
-		d.quant[i].uv[0] = dequantTableDC[clip(q+dquvDC, 0, 117)]
-		d.quant[i].uv[1] = dequantTableAC[clip(q+dquvAC, 0, 127)]
-	}
-}
-
-// The dequantization tables are specified in section 14.1.
-var (
-	dequantTableDC = [128]uint16{
-		4, 5, 6, 7, 8, 9, 10, 10,
-		11, 12, 13, 14, 15, 16, 17, 17,
-		18, 19, 20, 20, 21, 21, 22, 22,
-		23, 23, 24, 25, 25, 26, 27, 28,
-		29, 30, 31, 32, 33, 34, 35, 36,
-		37, 37, 38, 39, 40, 41, 42, 43,
-		44, 45, 46, 46, 47, 48, 49, 50,
-		51, 52, 53, 54, 55, 56, 57, 58,
-		59, 60, 61, 62, 63, 64, 65, 66,
-		67, 68, 69, 70, 71, 72, 73, 74,
-		75, 76, 76, 77, 78, 79, 80, 81,
-		82, 83, 84, 85, 86, 87, 88, 89,
-		91, 93, 95, 96, 98, 100, 101, 102,
-		104, 106, 108, 110, 112, 114, 116, 118,
-		122, 124, 126, 128, 130, 132, 134, 136,
-		138, 140, 143, 145, 148, 151, 154, 157,
-	}
-	dequantTableAC = [128]uint16{
-		4, 5, 6, 7, 8, 9, 10, 11,
-		12, 13, 14, 15, 16, 17, 18, 19,
-		20, 21, 22, 23, 24, 25, 26, 27,
-		28, 29, 30, 31, 32, 33, 34, 35,
-		36, 37, 38, 39, 40, 41, 42, 43,
-		44, 45, 46, 47, 48, 49, 50, 51,
-		52, 53, 54, 55, 56, 57, 58, 60,
-		62, 64, 66, 68, 70, 72, 74, 76,
-		78, 80, 82, 84, 86, 88, 90, 92,
-		94, 96, 98, 100, 102, 104, 106, 108,
-		110, 112, 114, 116, 119, 122, 125, 128,
-		131, 134, 137, 140, 143, 146, 149, 152,
-		155, 158, 161, 164, 167, 170, 173, 177,
-		181, 185, 189, 193, 197, 201, 205, 209,
-		213, 217, 221, 225, 229, 234, 239, 245,
-		249, 254, 259, 264, 269, 274, 279, 284,
-	}
-)
diff --git a/vendor/golang.org/x/image/vp8/reconstruct.go b/vendor/golang.org/x/image/vp8/reconstruct.go
deleted file mode 100644
index c1cc4b532..000000000
--- a/vendor/golang.org/x/image/vp8/reconstruct.go
+++ /dev/null
@@ -1,442 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package vp8
-
-// This file implements decoding DCT/WHT residual coefficients and
-// reconstructing YCbCr data equal to predicted values plus residuals.
-//
-// There are 1*16*16 + 2*8*8 + 1*4*4 coefficients per macroblock:
-//	- 1*16*16 luma DCT coefficients,
-//	- 2*8*8 chroma DCT coefficients, and
-//	- 1*4*4 luma WHT coefficients.
-// Coefficients are read in lots of 16, and the later coefficients in each lot
-// are often zero.
-//
-// The YCbCr data consists of 1*16*16 luma values and 2*8*8 chroma values,
-// plus previously decoded values along the top and left borders. The combined
-// values are laid out as a [1+16+1+8][32]uint8 so that vertically adjacent
-// samples are 32 bytes apart. In detail, the layout is:
-//
-//	0 1 2 3 4 5 6 7  8 9 0 1 2 3 4 5  6 7 8 9 0 1 2 3  4 5 6 7 8 9 0 1
-//	. . . . . . . a  b b b b b b b b  b b b b b b b b  c c c c . . . .	0
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	1
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	2
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	3
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  c c c c . . . .	4
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	5
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	6
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	7
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  c c c c . . . .	8
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	9
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	10
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	11
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  c c c c . . . .	12
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	13
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	14
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	15
-//	. . . . . . . d  Y Y Y Y Y Y Y Y  Y Y Y Y Y Y Y Y  . . . . . . . .	16
-//	. . . . . . . e  f f f f f f f f  . . . . . . . g  h h h h h h h h	17
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	18
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	19
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	20
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	21
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	22
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	23
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	24
-//	. . . . . . . i  B B B B B B B B  . . . . . . . j  R R R R R R R R	25
-//
-// Y, B and R are the reconstructed luma (Y) and chroma (B, R) values.
-// The Y values are predicted (either as one 16x16 region or 16 4x4 regions)
-// based on the row above's Y values (some combination of {abc} or {dYC}) and
-// the column left's Y values (either {ad} or {bY}). Similarly, B and R values
-// are predicted on the row above and column left of their respective 8x8
-// region: {efi} for B, {ghj} for R.
-//
-// For uppermost macroblocks (i.e. those with mby == 0), the {abcefgh} values
-// are initialized to 0x81. Otherwise, they are copied from the bottom row of
-// the macroblock above. The {c} values are then duplicated from row 0 to rows
-// 4, 8 and 12 of the ybr workspace.
-// Similarly, for leftmost macroblocks (i.e. those with mbx == 0), the {adeigj}
-// values are initialized to 0x7f. Otherwise, they are copied from the right
-// column of the macroblock to the left.
-// For the top-left macroblock (with mby == 0 && mbx == 0), {aeg} is 0x81.
-//
-// When moving from one macroblock to the next horizontally, the {adeigj}
-// values can simply be copied from the workspace to itself, shifted by 8 or
-// 16 columns. When moving from one macroblock to the next vertically,
-// filtering can occur and hence the row values have to be copied from the
-// post-filtered image instead of the pre-filtered workspace.
-
-const (
-	bCoeffBase   = 1*16*16 + 0*8*8
-	rCoeffBase   = 1*16*16 + 1*8*8
-	whtCoeffBase = 1*16*16 + 2*8*8
-)
-
-const (
-	ybrYX = 8
-	ybrYY = 1
-	ybrBX = 8
-	ybrBY = 18
-	ybrRX = 24
-	ybrRY = 18
-)
-
-// prepareYBR prepares the {abcdefghij} elements of ybr.
-func (d *Decoder) prepareYBR(mbx, mby int) {
-	if mbx == 0 {
-		for y := 0; y < 17; y++ {
-			d.ybr[y][7] = 0x81
-		}
-		for y := 17; y < 26; y++ {
-			d.ybr[y][7] = 0x81
-			d.ybr[y][23] = 0x81
-		}
-	} else {
-		for y := 0; y < 17; y++ {
-			d.ybr[y][7] = d.ybr[y][7+16]
-		}
-		for y := 17; y < 26; y++ {
-			d.ybr[y][7] = d.ybr[y][15]
-			d.ybr[y][23] = d.ybr[y][31]
-		}
-	}
-	if mby == 0 {
-		for x := 7; x < 28; x++ {
-			d.ybr[0][x] = 0x7f
-		}
-		for x := 7; x < 16; x++ {
-			d.ybr[17][x] = 0x7f
-		}
-		for x := 23; x < 32; x++ {
-			d.ybr[17][x] = 0x7f
-		}
-	} else {
-		for i := 0; i < 16; i++ {
-			d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+i]
-		}
-		for i := 0; i < 8; i++ {
-			d.ybr[17][8+i] = d.img.Cb[(8*mby-1)*d.img.CStride+8*mbx+i]
-		}
-		for i := 0; i < 8; i++ {
-			d.ybr[17][24+i] = d.img.Cr[(8*mby-1)*d.img.CStride+8*mbx+i]
-		}
-		if mbx == d.mbw-1 {
-			for i := 16; i < 20; i++ {
-				d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+15]
-			}
-		} else {
-			for i := 16; i < 20; i++ {
-				d.ybr[0][8+i] = d.img.Y[(16*mby-1)*d.img.YStride+16*mbx+i]
-			}
-		}
-	}
-	for y := 4; y < 16; y += 4 {
-		d.ybr[y][24] = d.ybr[0][24]
-		d.ybr[y][25] = d.ybr[0][25]
-		d.ybr[y][26] = d.ybr[0][26]
-		d.ybr[y][27] = d.ybr[0][27]
-	}
-}
-
-// btou converts a bool to a 0/1 value.
-func btou(b bool) uint8 {
-	if b {
-		return 1
-	}
-	return 0
-}
-
-// pack packs four 0/1 values into four bits of a uint32.
-func pack(x [4]uint8, shift int) uint32 {
-	u := uint32(x[0])<<0 | uint32(x[1])<<1 | uint32(x[2])<<2 | uint32(x[3])<<3
-	return u << uint(shift)
-}
-
-// unpack unpacks four 0/1 values from a four-bit value.
-var unpack = [16][4]uint8{
-	{0, 0, 0, 0},
-	{1, 0, 0, 0},
-	{0, 1, 0, 0},
-	{1, 1, 0, 0},
-	{0, 0, 1, 0},
-	{1, 0, 1, 0},
-	{0, 1, 1, 0},
-	{1, 1, 1, 0},
-	{0, 0, 0, 1},
-	{1, 0, 0, 1},
-	{0, 1, 0, 1},
-	{1, 1, 0, 1},
-	{0, 0, 1, 1},
-	{1, 0, 1, 1},
-	{0, 1, 1, 1},
-	{1, 1, 1, 1},
-}
-
-var (
-	// The mapping from 4x4 region position to band is specified in section 13.3.
-	bands = [17]uint8{0, 1, 2, 3, 6, 4, 5, 6, 6, 6, 6, 6, 6, 6, 6, 7, 0}
-	// Category probabilties are specified in section 13.2.
-	// Decoding categories 1 and 2 are done inline.
-	cat3456 = [4][12]uint8{
-		{173, 148, 140, 0, 0, 0, 0, 0, 0, 0, 0, 0},
-		{176, 155, 140, 135, 0, 0, 0, 0, 0, 0, 0, 0},
-		{180, 157, 141, 134, 130, 0, 0, 0, 0, 0, 0, 0},
-		{254, 254, 243, 230, 196, 177, 153, 140, 133, 130, 129, 0},
-	}
-	// The zigzag order is:
-	//	0  1  5  6
-	//	2  4  7 12
-	//	3  8 11 13
-	//	9 10 14 15
-	zigzag = [16]uint8{0, 1, 4, 8, 5, 2, 3, 6, 9, 12, 13, 10, 7, 11, 14, 15}
-)
-
-// parseResiduals4 parses a 4x4 region of residual coefficients, as specified
-// in section 13.3, and returns a 0/1 value indicating whether there was at
-// least one non-zero coefficient.
-// r is the partition to read bits from.
-// plane and context describe which token probability table to use. context is
-// either 0, 1 or 2, and equals how many of the macroblock left and macroblock
-// above have non-zero coefficients.
-// quant are the DC/AC quantization factors.
-// skipFirstCoeff is whether the DC coefficient has already been parsed.
-// coeffBase is the base index of d.coeff to write to.
-func (d *Decoder) parseResiduals4(r *partition, plane int, context uint8, quant [2]uint16, skipFirstCoeff bool, coeffBase int) uint8 {
-	prob, n := &d.tokenProb[plane], 0
-	if skipFirstCoeff {
-		n = 1
-	}
-	p := prob[bands[n]][context]
-	if !r.readBit(p[0]) {
-		return 0
-	}
-	for n != 16 {
-		n++
-		if !r.readBit(p[1]) {
-			p = prob[bands[n]][0]
-			continue
-		}
-		var v uint32
-		if !r.readBit(p[2]) {
-			v = 1
-			p = prob[bands[n]][1]
-		} else {
-			if !r.readBit(p[3]) {
-				if !r.readBit(p[4]) {
-					v = 2
-				} else {
-					v = 3 + r.readUint(p[5], 1)
-				}
-			} else if !r.readBit(p[6]) {
-				if !r.readBit(p[7]) {
-					// Category 1.
-					v = 5 + r.readUint(159, 1)
-				} else {
-					// Category 2.
-					v = 7 + 2*r.readUint(165, 1) + r.readUint(145, 1)
-				}
-			} else {
-				// Categories 3, 4, 5 or 6.
-				b1 := r.readUint(p[8], 1)
-				b0 := r.readUint(p[9+b1], 1)
-				cat := 2*b1 + b0
-				tab := &cat3456[cat]
-				v = 0
-				for i := 0; tab[i] != 0; i++ {
-					v *= 2
-					v += r.readUint(tab[i], 1)
-				}
-				v += 3 + (8 << cat)
-			}
-			p = prob[bands[n]][2]
-		}
-		z := zigzag[n-1]
-		c := int32(v) * int32(quant[btou(z > 0)])
-		if r.readBit(uniformProb) {
-			c = -c
-		}
-		d.coeff[coeffBase+int(z)] = int16(c)
-		if n == 16 || !r.readBit(p[0]) {
-			return 1
-		}
-	}
-	return 1
-}
-
-// parseResiduals parses the residuals and returns whether inner loop filtering
-// should be skipped for this macroblock.
-func (d *Decoder) parseResiduals(mbx, mby int) (skip bool) {
-	partition := &d.op[mby&(d.nOP-1)]
-	plane := planeY1SansY2
-	quant := &d.quant[d.segment]
-
-	// Parse the DC coefficient of each 4x4 luma region.
-	if d.usePredY16 {
-		nz := d.parseResiduals4(partition, planeY2, d.leftMB.nzY16+d.upMB[mbx].nzY16, quant.y2, false, whtCoeffBase)
-		d.leftMB.nzY16 = nz
-		d.upMB[mbx].nzY16 = nz
-		d.inverseWHT16()
-		plane = planeY1WithY2
-	}
-
-	var (
-		nzDC, nzAC         [4]uint8
-		nzDCMask, nzACMask uint32
-		coeffBase          int
-	)
-
-	// Parse the luma coefficients.
-	lnz := unpack[d.leftMB.nzMask&0x0f]
-	unz := unpack[d.upMB[mbx].nzMask&0x0f]
-	for y := 0; y < 4; y++ {
-		nz := lnz[y]
-		for x := 0; x < 4; x++ {
-			nz = d.parseResiduals4(partition, plane, nz+unz[x], quant.y1, d.usePredY16, coeffBase)
-			unz[x] = nz
-			nzAC[x] = nz
-			nzDC[x] = btou(d.coeff[coeffBase] != 0)
-			coeffBase += 16
-		}
-		lnz[y] = nz
-		nzDCMask |= pack(nzDC, y*4)
-		nzACMask |= pack(nzAC, y*4)
-	}
-	lnzMask := pack(lnz, 0)
-	unzMask := pack(unz, 0)
-
-	// Parse the chroma coefficients.
-	lnz = unpack[d.leftMB.nzMask>>4]
-	unz = unpack[d.upMB[mbx].nzMask>>4]
-	for c := 0; c < 4; c += 2 {
-		for y := 0; y < 2; y++ {
-			nz := lnz[y+c]
-			for x := 0; x < 2; x++ {
-				nz = d.parseResiduals4(partition, planeUV, nz+unz[x+c], quant.uv, false, coeffBase)
-				unz[x+c] = nz
-				nzAC[y*2+x] = nz
-				nzDC[y*2+x] = btou(d.coeff[coeffBase] != 0)
-				coeffBase += 16
-			}
-			lnz[y+c] = nz
-		}
-		nzDCMask |= pack(nzDC, 16+c*2)
-		nzACMask |= pack(nzAC, 16+c*2)
-	}
-	lnzMask |= pack(lnz, 4)
-	unzMask |= pack(unz, 4)
-
-	// Save decoder state.
-	d.leftMB.nzMask = uint8(lnzMask)
-	d.upMB[mbx].nzMask = uint8(unzMask)
-	d.nzDCMask = nzDCMask
-	d.nzACMask = nzACMask
-
-	// Section 15.1 of the spec says that "Steps 2 and 4 [of the loop filter]
-	// are skipped... [if] there is no DCT coefficient coded for the whole
-	// macroblock."
-	return nzDCMask == 0 && nzACMask == 0
-}
-
-// reconstructMacroblock applies the predictor functions and adds the inverse-
-// DCT transformed residuals to recover the YCbCr data.
-func (d *Decoder) reconstructMacroblock(mbx, mby int) {
-	if d.usePredY16 {
-		p := checkTopLeftPred(mbx, mby, d.predY16)
-		predFunc16[p](d, 1, 8)
-		for j := 0; j < 4; j++ {
-			for i := 0; i < 4; i++ {
-				n := 4*j + i
-				y := 4*j + 1
-				x := 4*i + 8
-				mask := uint32(1) << uint(n)
-				if d.nzACMask&mask != 0 {
-					d.inverseDCT4(y, x, 16*n)
-				} else if d.nzDCMask&mask != 0 {
-					d.inverseDCT4DCOnly(y, x, 16*n)
-				}
-			}
-		}
-	} else {
-		for j := 0; j < 4; j++ {
-			for i := 0; i < 4; i++ {
-				n := 4*j + i
-				y := 4*j + 1
-				x := 4*i + 8
-				predFunc4[d.predY4[j][i]](d, y, x)
-				mask := uint32(1) << uint(n)
-				if d.nzACMask&mask != 0 {
-					d.inverseDCT4(y, x, 16*n)
-				} else if d.nzDCMask&mask != 0 {
-					d.inverseDCT4DCOnly(y, x, 16*n)
-				}
-			}
-		}
-	}
-	p := checkTopLeftPred(mbx, mby, d.predC8)
-	predFunc8[p](d, ybrBY, ybrBX)
-	if d.nzACMask&0x0f0000 != 0 {
-		d.inverseDCT8(ybrBY, ybrBX, bCoeffBase)
-	} else if d.nzDCMask&0x0f0000 != 0 {
-		d.inverseDCT8DCOnly(ybrBY, ybrBX, bCoeffBase)
-	}
-	predFunc8[p](d, ybrRY, ybrRX)
-	if d.nzACMask&0xf00000 != 0 {
-		d.inverseDCT8(ybrRY, ybrRX, rCoeffBase)
-	} else if d.nzDCMask&0xf00000 != 0 {
-		d.inverseDCT8DCOnly(ybrRY, ybrRX, rCoeffBase)
-	}
-}
-
-// reconstruct reconstructs one macroblock and returns whether inner loop
-// filtering should be skipped for it.
-func (d *Decoder) reconstruct(mbx, mby int) (skip bool) {
-	if d.segmentHeader.updateMap {
-		if !d.fp.readBit(d.segmentHeader.prob[0]) {
-			d.segment = int(d.fp.readUint(d.segmentHeader.prob[1], 1))
-		} else {
-			d.segment = int(d.fp.readUint(d.segmentHeader.prob[2], 1)) + 2
-		}
-	}
-	if d.useSkipProb {
-		skip = d.fp.readBit(d.skipProb)
-	}
-	// Prepare the workspace.
-	for i := range d.coeff {
-		d.coeff[i] = 0
-	}
-	d.prepareYBR(mbx, mby)
-	// Parse the predictor modes.
-	d.usePredY16 = d.fp.readBit(145)
-	if d.usePredY16 {
-		d.parsePredModeY16(mbx)
-	} else {
-		d.parsePredModeY4(mbx)
-	}
-	d.parsePredModeC8()
-	// Parse the residuals.
-	if !skip {
-		skip = d.parseResiduals(mbx, mby)
-	} else {
-		if d.usePredY16 {
-			d.leftMB.nzY16 = 0
-			d.upMB[mbx].nzY16 = 0
-		}
-		d.leftMB.nzMask = 0
-		d.upMB[mbx].nzMask = 0
-		d.nzDCMask = 0
-		d.nzACMask = 0
-	}
-	// Reconstruct the YCbCr data and copy it to the image.
-	d.reconstructMacroblock(mbx, mby)
-	for i, y := (mby*d.img.YStride+mbx)*16, 0; y < 16; i, y = i+d.img.YStride, y+1 {
-		copy(d.img.Y[i:i+16], d.ybr[ybrYY+y][ybrYX:ybrYX+16])
-	}
-	for i, y := (mby*d.img.CStride+mbx)*8, 0; y < 8; i, y = i+d.img.CStride, y+1 {
-		copy(d.img.Cb[i:i+8], d.ybr[ybrBY+y][ybrBX:ybrBX+8])
-		copy(d.img.Cr[i:i+8], d.ybr[ybrRY+y][ybrRX:ybrRX+8])
-	}
-	return skip
-}
diff --git a/vendor/golang.org/x/image/vp8/token.go b/vendor/golang.org/x/image/vp8/token.go
deleted file mode 100644
index da99cf0f9..000000000
--- a/vendor/golang.org/x/image/vp8/token.go
+++ /dev/null
@@ -1,381 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package vp8
-
-// This file contains token probabilities for decoding DCT/WHT coefficients, as
-// specified in chapter 13.
-
-func (d *Decoder) parseTokenProb() {
-	for i := range d.tokenProb {
-		for j := range d.tokenProb[i] {
-			for k := range d.tokenProb[i][j] {
-				for l := range d.tokenProb[i][j][k] {
-					if d.fp.readBit(tokenProbUpdateProb[i][j][k][l]) {
-						d.tokenProb[i][j][k][l] = uint8(d.fp.readUint(uniformProb, 8))
-					}
-				}
-			}
-		}
-	}
-}
-
-// The plane enumeration is specified in section 13.3.
-const (
-	planeY1WithY2 = iota
-	planeY2
-	planeUV
-	planeY1SansY2
-	nPlane
-)
-
-const (
-	nBand    = 8
-	nContext = 3
-	nProb    = 11
-)
-
-// Token probability update probabilities are specified in section 13.4.
-var tokenProbUpdateProb = [nPlane][nBand][nContext][nProb]uint8{
-	{
-		{
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{176, 246, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{223, 241, 252, 255, 255, 255, 255, 255, 255, 255, 255},
-			{249, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 244, 252, 255, 255, 255, 255, 255, 255, 255, 255},
-			{234, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 246, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{239, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{251, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{251, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{254, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 254, 253, 255, 254, 255, 255, 255, 255, 255, 255},
-			{250, 255, 254, 255, 254, 255, 255, 255, 255, 255, 255},
-			{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-	},
-	{
-		{
-			{217, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{225, 252, 241, 253, 255, 255, 254, 255, 255, 255, 255},
-			{234, 250, 241, 250, 253, 255, 253, 254, 255, 255, 255},
-		},
-		{
-			{255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{223, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{238, 253, 254, 254, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 248, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{249, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 253, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{247, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{252, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{253, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255},
-			{250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-	},
-	{
-		{
-			{186, 251, 250, 255, 255, 255, 255, 255, 255, 255, 255},
-			{234, 251, 244, 254, 255, 255, 255, 255, 255, 255, 255},
-			{251, 251, 243, 253, 254, 255, 254, 255, 255, 255, 255},
-		},
-		{
-			{255, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{236, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{251, 253, 253, 254, 254, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{254, 254, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{254, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-	},
-	{
-		{
-			{248, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{250, 254, 252, 254, 255, 255, 255, 255, 255, 255, 255},
-			{248, 254, 249, 253, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255},
-			{246, 253, 253, 255, 255, 255, 255, 255, 255, 255, 255},
-			{252, 254, 251, 254, 254, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 254, 252, 255, 255, 255, 255, 255, 255, 255, 255},
-			{248, 254, 253, 255, 255, 255, 255, 255, 255, 255, 255},
-			{253, 255, 254, 254, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{245, 251, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{253, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 251, 253, 255, 255, 255, 255, 255, 255, 255, 255},
-			{252, 253, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 254, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 252, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{249, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 254, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 255, 253, 255, 255, 255, 255, 255, 255, 255, 255},
-			{250, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-		{
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{254, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-			{255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255},
-		},
-	},
-}
-
-// Default token probabilities are specified in section 13.5.
-var defaultTokenProb = [nPlane][nBand][nContext][nProb]uint8{
-	{
-		{
-			{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
-			{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
-			{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
-		},
-		{
-			{253, 136, 254, 255, 228, 219, 128, 128, 128, 128, 128},
-			{189, 129, 242, 255, 227, 213, 255, 219, 128, 128, 128},
-			{106, 126, 227, 252, 214, 209, 255, 255, 128, 128, 128},
-		},
-		{
-			{1, 98, 248, 255, 236, 226, 255, 255, 128, 128, 128},
-			{181, 133, 238, 254, 221, 234, 255, 154, 128, 128, 128},
-			{78, 134, 202, 247, 198, 180, 255, 219, 128, 128, 128},
-		},
-		{
-			{1, 185, 249, 255, 243, 255, 128, 128, 128, 128, 128},
-			{184, 150, 247, 255, 236, 224, 128, 128, 128, 128, 128},
-			{77, 110, 216, 255, 236, 230, 128, 128, 128, 128, 128},
-		},
-		{
-			{1, 101, 251, 255, 241, 255, 128, 128, 128, 128, 128},
-			{170, 139, 241, 252, 236, 209, 255, 255, 128, 128, 128},
-			{37, 116, 196, 243, 228, 255, 255, 255, 128, 128, 128},
-		},
-		{
-			{1, 204, 254, 255, 245, 255, 128, 128, 128, 128, 128},
-			{207, 160, 250, 255, 238, 128, 128, 128, 128, 128, 128},
-			{102, 103, 231, 255, 211, 171, 128, 128, 128, 128, 128},
-		},
-		{
-			{1, 152, 252, 255, 240, 255, 128, 128, 128, 128, 128},
-			{177, 135, 243, 255, 234, 225, 128, 128, 128, 128, 128},
-			{80, 129, 211, 255, 194, 224, 128, 128, 128, 128, 128},
-		},
-		{
-			{1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
-			{246, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
-			{255, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
-		},
-	},
-	{
-		{
-			{198, 35, 237, 223, 193, 187, 162, 160, 145, 155, 62},
-			{131, 45, 198, 221, 172, 176, 220, 157, 252, 221, 1},
-			{68, 47, 146, 208, 149, 167, 221, 162, 255, 223, 128},
-		},
-		{
-			{1, 149, 241, 255, 221, 224, 255, 255, 128, 128, 128},
-			{184, 141, 234, 253, 222, 220, 255, 199, 128, 128, 128},
-			{81, 99, 181, 242, 176, 190, 249, 202, 255, 255, 128},
-		},
-		{
-			{1, 129, 232, 253, 214, 197, 242, 196, 255, 255, 128},
-			{99, 121, 210, 250, 201, 198, 255, 202, 128, 128, 128},
-			{23, 91, 163, 242, 170, 187, 247, 210, 255, 255, 128},
-		},
-		{
-			{1, 200, 246, 255, 234, 255, 128, 128, 128, 128, 128},
-			{109, 178, 241, 255, 231, 245, 255, 255, 128, 128, 128},
-			{44, 130, 201, 253, 205, 192, 255, 255, 128, 128, 128},
-		},
-		{
-			{1, 132, 239, 251, 219, 209, 255, 165, 128, 128, 128},
-			{94, 136, 225, 251, 218, 190, 255, 255, 128, 128, 128},
-			{22, 100, 174, 245, 186, 161, 255, 199, 128, 128, 128},
-		},
-		{
-			{1, 182, 249, 255, 232, 235, 128, 128, 128, 128, 128},
-			{124, 143, 241, 255, 227, 234, 128, 128, 128, 128, 128},
-			{35, 77, 181, 251, 193, 211, 255, 205, 128, 128, 128},
-		},
-		{
-			{1, 157, 247, 255, 236, 231, 255, 255, 128, 128, 128},
-			{121, 141, 235, 255, 225, 227, 255, 255, 128, 128, 128},
-			{45, 99, 188, 251, 195, 217, 255, 224, 128, 128, 128},
-		},
-		{
-			{1, 1, 251, 255, 213, 255, 128, 128, 128, 128, 128},
-			{203, 1, 248, 255, 255, 128, 128, 128, 128, 128, 128},
-			{137, 1, 177, 255, 224, 255, 128, 128, 128, 128, 128},
-		},
-	},
-	{
-		{
-			{253, 9, 248, 251, 207, 208, 255, 192, 128, 128, 128},
-			{175, 13, 224, 243, 193, 185, 249, 198, 255, 255, 128},
-			{73, 17, 171, 221, 161, 179, 236, 167, 255, 234, 128},
-		},
-		{
-			{1, 95, 247, 253, 212, 183, 255, 255, 128, 128, 128},
-			{239, 90, 244, 250, 211, 209, 255, 255, 128, 128, 128},
-			{155, 77, 195, 248, 188, 195, 255, 255, 128, 128, 128},
-		},
-		{
-			{1, 24, 239, 251, 218, 219, 255, 205, 128, 128, 128},
-			{201, 51, 219, 255, 196, 186, 128, 128, 128, 128, 128},
-			{69, 46, 190, 239, 201, 218, 255, 228, 128, 128, 128},
-		},
-		{
-			{1, 191, 251, 255, 255, 128, 128, 128, 128, 128, 128},
-			{223, 165, 249, 255, 213, 255, 128, 128, 128, 128, 128},
-			{141, 124, 248, 255, 255, 128, 128, 128, 128, 128, 128},
-		},
-		{
-			{1, 16, 248, 255, 255, 128, 128, 128, 128, 128, 128},
-			{190, 36, 230, 255, 236, 255, 128, 128, 128, 128, 128},
-			{149, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
-		},
-		{
-			{1, 226, 255, 128, 128, 128, 128, 128, 128, 128, 128},
-			{247, 192, 255, 128, 128, 128, 128, 128, 128, 128, 128},
-			{240, 128, 255, 128, 128, 128, 128, 128, 128, 128, 128},
-		},
-		{
-			{1, 134, 252, 255, 255, 128, 128, 128, 128, 128, 128},
-			{213, 62, 250, 255, 255, 128, 128, 128, 128, 128, 128},
-			{55, 93, 255, 128, 128, 128, 128, 128, 128, 128, 128},
-		},
-		{
-			{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
-			{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
-			{128, 128, 128, 128, 128, 128, 128, 128, 128, 128, 128},
-		},
-	},
-	{
-		{
-			{202, 24, 213, 235, 186, 191, 220, 160, 240, 175, 255},
-			{126, 38, 182, 232, 169, 184, 228, 174, 255, 187, 128},
-			{61, 46, 138, 219, 151, 178, 240, 170, 255, 216, 128},
-		},
-		{
-			{1, 112, 230, 250, 199, 191, 247, 159, 255, 255, 128},
-			{166, 109, 228, 252, 211, 215, 255, 174, 128, 128, 128},
-			{39, 77, 162, 232, 172, 180, 245, 178, 255, 255, 128},
-		},
-		{
-			{1, 52, 220, 246, 198, 199, 249, 220, 255, 255, 128},
-			{124, 74, 191, 243, 183, 193, 250, 221, 255, 255, 128},
-			{24, 71, 130, 219, 154, 170, 243, 182, 255, 255, 128},
-		},
-		{
-			{1, 182, 225, 249, 219, 240, 255, 224, 128, 128, 128},
-			{149, 150, 226, 252, 216, 205, 255, 171, 128, 128, 128},
-			{28, 108, 170, 242, 183, 194, 254, 223, 255, 255, 128},
-		},
-		{
-			{1, 81, 230, 252, 204, 203, 255, 192, 128, 128, 128},
-			{123, 102, 209, 247, 188, 196, 255, 233, 128, 128, 128},
-			{20, 95, 153, 243, 164, 173, 255, 203, 128, 128, 128},
-		},
-		{
-			{1, 222, 248, 255, 216, 213, 128, 128, 128, 128, 128},
-			{168, 175, 246, 252, 235, 205, 255, 255, 128, 128, 128},
-			{47, 116, 215, 255, 211, 212, 255, 255, 128, 128, 128},
-		},
-		{
-			{1, 121, 236, 253, 212, 214, 255, 255, 128, 128, 128},
-			{141, 84, 213, 252, 201, 202, 255, 219, 128, 128, 128},
-			{42, 80, 160, 240, 162, 185, 255, 205, 128, 128, 128},
-		},
-		{
-			{1, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
-			{244, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
-			{238, 1, 255, 128, 128, 128, 128, 128, 128, 128, 128},
-		},
-	},
-}
diff --git a/vendor/golang.org/x/image/vp8l/decode.go b/vendor/golang.org/x/image/vp8l/decode.go
deleted file mode 100644
index 431948701..000000000
--- a/vendor/golang.org/x/image/vp8l/decode.go
+++ /dev/null
@@ -1,603 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package vp8l implements a decoder for the VP8L lossless image format.
-//
-// The VP8L specification is at:
-// https://developers.google.com/speed/webp/docs/riff_container
-package vp8l // import "golang.org/x/image/vp8l"
-
-import (
-	"bufio"
-	"errors"
-	"image"
-	"image/color"
-	"io"
-)
-
-var (
-	errInvalidCodeLengths = errors.New("vp8l: invalid code lengths")
-	errInvalidHuffmanTree = errors.New("vp8l: invalid Huffman tree")
-)
-
-// colorCacheMultiplier is the multiplier used for the color cache hash
-// function, specified in section 4.2.3.
-const colorCacheMultiplier = 0x1e35a7bd
-
-// distanceMapTable is the look-up table for distanceMap.
-var distanceMapTable = [120]uint8{
-	0x18, 0x07, 0x17, 0x19, 0x28, 0x06, 0x27, 0x29, 0x16, 0x1a,
-	0x26, 0x2a, 0x38, 0x05, 0x37, 0x39, 0x15, 0x1b, 0x36, 0x3a,
-	0x25, 0x2b, 0x48, 0x04, 0x47, 0x49, 0x14, 0x1c, 0x35, 0x3b,
-	0x46, 0x4a, 0x24, 0x2c, 0x58, 0x45, 0x4b, 0x34, 0x3c, 0x03,
-	0x57, 0x59, 0x13, 0x1d, 0x56, 0x5a, 0x23, 0x2d, 0x44, 0x4c,
-	0x55, 0x5b, 0x33, 0x3d, 0x68, 0x02, 0x67, 0x69, 0x12, 0x1e,
-	0x66, 0x6a, 0x22, 0x2e, 0x54, 0x5c, 0x43, 0x4d, 0x65, 0x6b,
-	0x32, 0x3e, 0x78, 0x01, 0x77, 0x79, 0x53, 0x5d, 0x11, 0x1f,
-	0x64, 0x6c, 0x42, 0x4e, 0x76, 0x7a, 0x21, 0x2f, 0x75, 0x7b,
-	0x31, 0x3f, 0x63, 0x6d, 0x52, 0x5e, 0x00, 0x74, 0x7c, 0x41,
-	0x4f, 0x10, 0x20, 0x62, 0x6e, 0x30, 0x73, 0x7d, 0x51, 0x5f,
-	0x40, 0x72, 0x7e, 0x61, 0x6f, 0x50, 0x71, 0x7f, 0x60, 0x70,
-}
-
-// distanceMap maps a LZ77 backwards reference distance to a two-dimensional
-// pixel offset, specified in section 4.2.2.
-func distanceMap(w int32, code uint32) int32 {
-	if int32(code) > int32(len(distanceMapTable)) {
-		return int32(code) - int32(len(distanceMapTable))
-	}
-	distCode := int32(distanceMapTable[code-1])
-	yOffset := distCode >> 4
-	xOffset := 8 - distCode&0xf
-	if d := yOffset*w + xOffset; d >= 1 {
-		return d
-	}
-	return 1
-}
-
-// decoder holds the bit-stream for a VP8L image.
-type decoder struct {
-	r     io.ByteReader
-	bits  uint32
-	nBits uint32
-}
-
-// read reads the next n bits from the decoder's bit-stream.
-func (d *decoder) read(n uint32) (uint32, error) {
-	for d.nBits < n {
-		c, err := d.r.ReadByte()
-		if err != nil {
-			if err == io.EOF {
-				err = io.ErrUnexpectedEOF
-			}
-			return 0, err
-		}
-		d.bits |= uint32(c) << d.nBits
-		d.nBits += 8
-	}
-	u := d.bits & (1<<n - 1)
-	d.bits >>= n
-	d.nBits -= n
-	return u, nil
-}
-
-// decodeTransform decodes the next transform and the width of the image after
-// transformation (or equivalently, before inverse transformation), specified
-// in section 3.
-func (d *decoder) decodeTransform(w int32, h int32) (t transform, newWidth int32, err error) {
-	t.oldWidth = w
-	t.transformType, err = d.read(2)
-	if err != nil {
-		return transform{}, 0, err
-	}
-	switch t.transformType {
-	case transformTypePredictor, transformTypeCrossColor:
-		t.bits, err = d.read(3)
-		if err != nil {
-			return transform{}, 0, err
-		}
-		t.bits += 2
-		t.pix, err = d.decodePix(nTiles(w, t.bits), nTiles(h, t.bits), 0, false)
-		if err != nil {
-			return transform{}, 0, err
-		}
-	case transformTypeSubtractGreen:
-		// No-op.
-	case transformTypeColorIndexing:
-		nColors, err := d.read(8)
-		if err != nil {
-			return transform{}, 0, err
-		}
-		nColors++
-		t.bits = 0
-		switch {
-		case nColors <= 2:
-			t.bits = 3
-		case nColors <= 4:
-			t.bits = 2
-		case nColors <= 16:
-			t.bits = 1
-		}
-		w = nTiles(w, t.bits)
-		pix, err := d.decodePix(int32(nColors), 1, 4*256, false)
-		if err != nil {
-			return transform{}, 0, err
-		}
-		for p := 4; p < len(pix); p += 4 {
-			pix[p+0] += pix[p-4]
-			pix[p+1] += pix[p-3]
-			pix[p+2] += pix[p-2]
-			pix[p+3] += pix[p-1]
-		}
-		// The spec says that "if the index is equal or larger than color_table_size,
-		// the argb color value should be set to 0x00000000 (transparent black)."
-		// We re-slice up to 256 4-byte pixels.
-		t.pix = pix[:4*256]
-	}
-	return t, w, nil
-}
-
-// repeatsCodeLength is the minimum code length for repeated codes.
-const repeatsCodeLength = 16
-
-// These magic numbers are specified at the end of section 5.2.2.
-// The 3-length arrays apply to code lengths >= repeatsCodeLength.
-var (
-	codeLengthCodeOrder = [19]uint8{
-		17, 18, 0, 1, 2, 3, 4, 5, 16, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
-	}
-	repeatBits    = [3]uint8{2, 3, 7}
-	repeatOffsets = [3]uint8{3, 3, 11}
-)
-
-// decodeCodeLengths decodes a Huffman tree's code lengths which are themselves
-// encoded via a Huffman tree, specified in section 5.2.2.
-func (d *decoder) decodeCodeLengths(dst []uint32, codeLengthCodeLengths []uint32) error {
-	h := hTree{}
-	if err := h.build(codeLengthCodeLengths); err != nil {
-		return err
-	}
-
-	maxSymbol := len(dst)
-	useLength, err := d.read(1)
-	if err != nil {
-		return err
-	}
-	if useLength != 0 {
-		n, err := d.read(3)
-		if err != nil {
-			return err
-		}
-		n = 2 + 2*n
-		ms, err := d.read(n)
-		if err != nil {
-			return err
-		}
-		maxSymbol = int(ms) + 2
-		if maxSymbol > len(dst) {
-			return errInvalidCodeLengths
-		}
-	}
-
-	// The spec says that "if code 16 [meaning repeat] is used before
-	// a non-zero value has been emitted, a value of 8 is repeated."
-	prevCodeLength := uint32(8)
-
-	for symbol := 0; symbol < len(dst); {
-		if maxSymbol == 0 {
-			break
-		}
-		maxSymbol--
-		codeLength, err := h.next(d)
-		if err != nil {
-			return err
-		}
-		if codeLength < repeatsCodeLength {
-			dst[symbol] = codeLength
-			symbol++
-			if codeLength != 0 {
-				prevCodeLength = codeLength
-			}
-			continue
-		}
-
-		repeat, err := d.read(uint32(repeatBits[codeLength-repeatsCodeLength]))
-		if err != nil {
-			return err
-		}
-		repeat += uint32(repeatOffsets[codeLength-repeatsCodeLength])
-		if symbol+int(repeat) > len(dst) {
-			return errInvalidCodeLengths
-		}
-		// A code length of 16 repeats the previous non-zero code.
-		// A code length of 17 or 18 repeats zeroes.
-		cl := uint32(0)
-		if codeLength == 16 {
-			cl = prevCodeLength
-		}
-		for ; repeat > 0; repeat-- {
-			dst[symbol] = cl
-			symbol++
-		}
-	}
-	return nil
-}
-
-// decodeHuffmanTree decodes a Huffman tree into h.
-func (d *decoder) decodeHuffmanTree(h *hTree, alphabetSize uint32) error {
-	useSimple, err := d.read(1)
-	if err != nil {
-		return err
-	}
-	if useSimple != 0 {
-		nSymbols, err := d.read(1)
-		if err != nil {
-			return err
-		}
-		nSymbols++
-		firstSymbolLengthCode, err := d.read(1)
-		if err != nil {
-			return err
-		}
-		firstSymbolLengthCode = 7*firstSymbolLengthCode + 1
-		var symbols [2]uint32
-		symbols[0], err = d.read(firstSymbolLengthCode)
-		if err != nil {
-			return err
-		}
-		if nSymbols == 2 {
-			symbols[1], err = d.read(8)
-			if err != nil {
-				return err
-			}
-		}
-		return h.buildSimple(nSymbols, symbols, alphabetSize)
-	}
-
-	nCodes, err := d.read(4)
-	if err != nil {
-		return err
-	}
-	nCodes += 4
-	if int(nCodes) > len(codeLengthCodeOrder) {
-		return errInvalidHuffmanTree
-	}
-	codeLengthCodeLengths := [len(codeLengthCodeOrder)]uint32{}
-	for i := uint32(0); i < nCodes; i++ {
-		codeLengthCodeLengths[codeLengthCodeOrder[i]], err = d.read(3)
-		if err != nil {
-			return err
-		}
-	}
-	codeLengths := make([]uint32, alphabetSize)
-	if err = d.decodeCodeLengths(codeLengths, codeLengthCodeLengths[:]); err != nil {
-		return err
-	}
-	return h.build(codeLengths)
-}
-
-const (
-	huffGreen    = 0
-	huffRed      = 1
-	huffBlue     = 2
-	huffAlpha    = 3
-	huffDistance = 4
-	nHuff        = 5
-)
-
-// hGroup is an array of 5 Huffman trees.
-type hGroup [nHuff]hTree
-
-// decodeHuffmanGroups decodes the one or more hGroups used to decode the pixel
-// data. If one hGroup is used for the entire image, then hPix and hBits will
-// be zero. If more than one hGroup is used, then hPix contains the meta-image
-// that maps tiles to hGroup index, and hBits contains the log-2 tile size.
-func (d *decoder) decodeHuffmanGroups(w int32, h int32, topLevel bool, ccBits uint32) (
-	hGroups []hGroup, hPix []byte, hBits uint32, err error) {
-
-	maxHGroupIndex := 0
-	if topLevel {
-		useMeta, err := d.read(1)
-		if err != nil {
-			return nil, nil, 0, err
-		}
-		if useMeta != 0 {
-			hBits, err = d.read(3)
-			if err != nil {
-				return nil, nil, 0, err
-			}
-			hBits += 2
-			hPix, err = d.decodePix(nTiles(w, hBits), nTiles(h, hBits), 0, false)
-			if err != nil {
-				return nil, nil, 0, err
-			}
-			for p := 0; p < len(hPix); p += 4 {
-				i := int(hPix[p])<<8 | int(hPix[p+1])
-				if maxHGroupIndex < i {
-					maxHGroupIndex = i
-				}
-			}
-		}
-	}
-	hGroups = make([]hGroup, maxHGroupIndex+1)
-	for i := range hGroups {
-		for j, alphabetSize := range alphabetSizes {
-			if j == 0 && ccBits > 0 {
-				alphabetSize += 1 << ccBits
-			}
-			if err := d.decodeHuffmanTree(&hGroups[i][j], alphabetSize); err != nil {
-				return nil, nil, 0, err
-			}
-		}
-	}
-	return hGroups, hPix, hBits, nil
-}
-
-const (
-	nLiteralCodes  = 256
-	nLengthCodes   = 24
-	nDistanceCodes = 40
-)
-
-var alphabetSizes = [nHuff]uint32{
-	nLiteralCodes + nLengthCodes,
-	nLiteralCodes,
-	nLiteralCodes,
-	nLiteralCodes,
-	nDistanceCodes,
-}
-
-// decodePix decodes pixel data, specified in section 5.2.2.
-func (d *decoder) decodePix(w int32, h int32, minCap int32, topLevel bool) ([]byte, error) {
-	// Decode the color cache parameters.
-	ccBits, ccShift, ccEntries := uint32(0), uint32(0), ([]uint32)(nil)
-	useColorCache, err := d.read(1)
-	if err != nil {
-		return nil, err
-	}
-	if useColorCache != 0 {
-		ccBits, err = d.read(4)
-		if err != nil {
-			return nil, err
-		}
-		if ccBits < 1 || 11 < ccBits {
-			return nil, errors.New("vp8l: invalid color cache parameters")
-		}
-		ccShift = 32 - ccBits
-		ccEntries = make([]uint32, 1<<ccBits)
-	}
-
-	// Decode the Huffman groups.
-	hGroups, hPix, hBits, err := d.decodeHuffmanGroups(w, h, topLevel, ccBits)
-	if err != nil {
-		return nil, err
-	}
-	hMask, tilesPerRow := int32(0), int32(0)
-	if hBits != 0 {
-		hMask, tilesPerRow = 1<<hBits-1, nTiles(w, hBits)
-	}
-
-	// Decode the pixels.
-	if minCap < 4*w*h {
-		minCap = 4 * w * h
-	}
-	pix := make([]byte, 4*w*h, minCap)
-	p, cachedP := 0, 0
-	x, y := int32(0), int32(0)
-	hg, lookupHG := &hGroups[0], hMask != 0
-	for p < len(pix) {
-		if lookupHG {
-			i := 4 * (tilesPerRow*(y>>hBits) + (x >> hBits))
-			hg = &hGroups[uint32(hPix[i])<<8|uint32(hPix[i+1])]
-		}
-
-		green, err := hg[huffGreen].next(d)
-		if err != nil {
-			return nil, err
-		}
-		switch {
-		case green < nLiteralCodes:
-			// We have a literal pixel.
-			red, err := hg[huffRed].next(d)
-			if err != nil {
-				return nil, err
-			}
-			blue, err := hg[huffBlue].next(d)
-			if err != nil {
-				return nil, err
-			}
-			alpha, err := hg[huffAlpha].next(d)
-			if err != nil {
-				return nil, err
-			}
-			pix[p+0] = uint8(red)
-			pix[p+1] = uint8(green)
-			pix[p+2] = uint8(blue)
-			pix[p+3] = uint8(alpha)
-			p += 4
-
-			x++
-			if x == w {
-				x, y = 0, y+1
-			}
-			lookupHG = hMask != 0 && x&hMask == 0
-
-		case green < nLiteralCodes+nLengthCodes:
-			// We have a LZ77 backwards reference.
-			length, err := d.lz77Param(green - nLiteralCodes)
-			if err != nil {
-				return nil, err
-			}
-			distSym, err := hg[huffDistance].next(d)
-			if err != nil {
-				return nil, err
-			}
-			distCode, err := d.lz77Param(distSym)
-			if err != nil {
-				return nil, err
-			}
-			dist := distanceMap(w, distCode)
-			pEnd := p + 4*int(length)
-			q := p - 4*int(dist)
-			qEnd := pEnd - 4*int(dist)
-			if p < 0 || len(pix) < pEnd || q < 0 || len(pix) < qEnd {
-				return nil, errors.New("vp8l: invalid LZ77 parameters")
-			}
-			for ; p < pEnd; p, q = p+1, q+1 {
-				pix[p] = pix[q]
-			}
-
-			x += int32(length)
-			for x >= w {
-				x, y = x-w, y+1
-			}
-			lookupHG = hMask != 0
-
-		default:
-			// We have a color cache lookup. First, insert previous pixels
-			// into the cache. Note that VP8L assumes ARGB order, but the
-			// Go image.RGBA type is in RGBA order.
-			for ; cachedP < p; cachedP += 4 {
-				argb := uint32(pix[cachedP+0])<<16 |
-					uint32(pix[cachedP+1])<<8 |
-					uint32(pix[cachedP+2])<<0 |
-					uint32(pix[cachedP+3])<<24
-				ccEntries[(argb*colorCacheMultiplier)>>ccShift] = argb
-			}
-			green -= nLiteralCodes + nLengthCodes
-			if int(green) >= len(ccEntries) {
-				return nil, errors.New("vp8l: invalid color cache index")
-			}
-			argb := ccEntries[green]
-			pix[p+0] = uint8(argb >> 16)
-			pix[p+1] = uint8(argb >> 8)
-			pix[p+2] = uint8(argb >> 0)
-			pix[p+3] = uint8(argb >> 24)
-			p += 4
-
-			x++
-			if x == w {
-				x, y = 0, y+1
-			}
-			lookupHG = hMask != 0 && x&hMask == 0
-		}
-	}
-	return pix, nil
-}
-
-// lz77Param returns the next LZ77 parameter: a length or a distance, specified
-// in section 4.2.2.
-func (d *decoder) lz77Param(symbol uint32) (uint32, error) {
-	if symbol < 4 {
-		return symbol + 1, nil
-	}
-	extraBits := (symbol - 2) >> 1
-	offset := (2 + symbol&1) << extraBits
-	n, err := d.read(extraBits)
-	if err != nil {
-		return 0, err
-	}
-	return offset + n + 1, nil
-}
-
-// decodeHeader decodes the VP8L header from r.
-func decodeHeader(r io.Reader) (d *decoder, w int32, h int32, err error) {
-	rr, ok := r.(io.ByteReader)
-	if !ok {
-		rr = bufio.NewReader(r)
-	}
-	d = &decoder{r: rr}
-	magic, err := d.read(8)
-	if err != nil {
-		return nil, 0, 0, err
-	}
-	if magic != 0x2f {
-		return nil, 0, 0, errors.New("vp8l: invalid header")
-	}
-	width, err := d.read(14)
-	if err != nil {
-		return nil, 0, 0, err
-	}
-	width++
-	height, err := d.read(14)
-	if err != nil {
-		return nil, 0, 0, err
-	}
-	height++
-	_, err = d.read(1) // Read and ignore the hasAlpha hint.
-	if err != nil {
-		return nil, 0, 0, err
-	}
-	version, err := d.read(3)
-	if err != nil {
-		return nil, 0, 0, err
-	}
-	if version != 0 {
-		return nil, 0, 0, errors.New("vp8l: invalid version")
-	}
-	return d, int32(width), int32(height), nil
-}
-
-// DecodeConfig decodes the color model and dimensions of a VP8L image from r.
-func DecodeConfig(r io.Reader) (image.Config, error) {
-	_, w, h, err := decodeHeader(r)
-	if err != nil {
-		return image.Config{}, err
-	}
-	return image.Config{
-		ColorModel: color.NRGBAModel,
-		Width:      int(w),
-		Height:     int(h),
-	}, nil
-}
-
-// Decode decodes a VP8L image from r.
-func Decode(r io.Reader) (image.Image, error) {
-	d, w, h, err := decodeHeader(r)
-	if err != nil {
-		return nil, err
-	}
-	// Decode the transforms.
-	var (
-		nTransforms    int
-		transforms     [nTransformTypes]transform
-		transformsSeen [nTransformTypes]bool
-		originalW      = w
-	)
-	for {
-		more, err := d.read(1)
-		if err != nil {
-			return nil, err
-		}
-		if more == 0 {
-			break
-		}
-		var t transform
-		t, w, err = d.decodeTransform(w, h)
-		if err != nil {
-			return nil, err
-		}
-		if transformsSeen[t.transformType] {
-			return nil, errors.New("vp8l: repeated transform")
-		}
-		transformsSeen[t.transformType] = true
-		transforms[nTransforms] = t
-		nTransforms++
-	}
-	// Decode the transformed pixels.
-	pix, err := d.decodePix(w, h, 0, true)
-	if err != nil {
-		return nil, err
-	}
-	// Apply the inverse transformations.
-	for i := nTransforms - 1; i >= 0; i-- {
-		t := &transforms[i]
-		pix = inverseTransforms[t.transformType](t, pix, h)
-	}
-	return &image.NRGBA{
-		Pix:    pix,
-		Stride: 4 * int(originalW),
-		Rect:   image.Rect(0, 0, int(originalW), int(h)),
-	}, nil
-}
diff --git a/vendor/golang.org/x/image/vp8l/huffman.go b/vendor/golang.org/x/image/vp8l/huffman.go
deleted file mode 100644
index 36368a872..000000000
--- a/vendor/golang.org/x/image/vp8l/huffman.go
+++ /dev/null
@@ -1,245 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package vp8l
-
-import (
-	"io"
-)
-
-// reverseBits reverses the bits in a byte.
-var reverseBits = [256]uint8{
-	0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0, 0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
-	0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8, 0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
-	0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4, 0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
-	0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec, 0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
-	0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2, 0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
-	0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea, 0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
-	0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6, 0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
-	0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee, 0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
-	0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1, 0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
-	0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9, 0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
-	0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5, 0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
-	0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed, 0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
-	0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3, 0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
-	0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb, 0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
-	0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7, 0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
-	0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef, 0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff,
-}
-
-// hNode is a node in a Huffman tree.
-type hNode struct {
-	// symbol is the symbol held by this node.
-	symbol uint32
-	// children, if positive, is the hTree.nodes index of the first of
-	// this node's two children. Zero means an uninitialized node,
-	// and -1 means a leaf node.
-	children int32
-}
-
-const leafNode = -1
-
-// lutSize is the log-2 size of an hTree's look-up table.
-const lutSize, lutMask = 7, 1<<7 - 1
-
-// hTree is a Huffman tree.
-type hTree struct {
-	// nodes are the nodes of the Huffman tree. During construction,
-	// len(nodes) grows from 1 up to cap(nodes) by steps of two.
-	// After construction, len(nodes) == cap(nodes), and both equal
-	// 2*theNumberOfSymbols - 1.
-	nodes []hNode
-	// lut is a look-up table for walking the nodes. The x in lut[x] is
-	// the next lutSize bits in the bit-stream. The low 8 bits of lut[x]
-	// equals 1 plus the number of bits in the next code, or 0 if the
-	// next code requires more than lutSize bits. The high 24 bits are:
-	//   - the symbol, if the code requires lutSize or fewer bits, or
-	//   - the hTree.nodes index to start the tree traversal from, if
-	//     the next code requires more than lutSize bits.
-	lut [1 << lutSize]uint32
-}
-
-// insert inserts into the hTree a symbol whose encoding is the least
-// significant codeLength bits of code.
-func (h *hTree) insert(symbol uint32, code uint32, codeLength uint32) error {
-	if symbol > 0xffff || codeLength > 0xfe {
-		return errInvalidHuffmanTree
-	}
-	baseCode := uint32(0)
-	if codeLength > lutSize {
-		baseCode = uint32(reverseBits[(code>>(codeLength-lutSize))&0xff]) >> (8 - lutSize)
-	} else {
-		baseCode = uint32(reverseBits[code&0xff]) >> (8 - codeLength)
-		for i := 0; i < 1<<(lutSize-codeLength); i++ {
-			h.lut[baseCode|uint32(i)<<codeLength] = symbol<<8 | (codeLength + 1)
-		}
-	}
-
-	n := uint32(0)
-	for jump := lutSize; codeLength > 0; {
-		codeLength--
-		if int(n) > len(h.nodes) {
-			return errInvalidHuffmanTree
-		}
-		switch h.nodes[n].children {
-		case leafNode:
-			return errInvalidHuffmanTree
-		case 0:
-			if len(h.nodes) == cap(h.nodes) {
-				return errInvalidHuffmanTree
-			}
-			// Create two empty child nodes.
-			h.nodes[n].children = int32(len(h.nodes))
-			h.nodes = h.nodes[:len(h.nodes)+2]
-		}
-		n = uint32(h.nodes[n].children) + 1&(code>>codeLength)
-		jump--
-		if jump == 0 && h.lut[baseCode] == 0 {
-			h.lut[baseCode] = n << 8
-		}
-	}
-
-	switch h.nodes[n].children {
-	case leafNode:
-		// No-op.
-	case 0:
-		// Turn the uninitialized node into a leaf.
-		h.nodes[n].children = leafNode
-	default:
-		return errInvalidHuffmanTree
-	}
-	h.nodes[n].symbol = symbol
-	return nil
-}
-
-// codeLengthsToCodes returns the canonical Huffman codes implied by the
-// sequence of code lengths.
-func codeLengthsToCodes(codeLengths []uint32) ([]uint32, error) {
-	maxCodeLength := uint32(0)
-	for _, cl := range codeLengths {
-		if maxCodeLength < cl {
-			maxCodeLength = cl
-		}
-	}
-	const maxAllowedCodeLength = 15
-	if len(codeLengths) == 0 || maxCodeLength > maxAllowedCodeLength {
-		return nil, errInvalidHuffmanTree
-	}
-	histogram := [maxAllowedCodeLength + 1]uint32{}
-	for _, cl := range codeLengths {
-		histogram[cl]++
-	}
-	currCode, nextCodes := uint32(0), [maxAllowedCodeLength + 1]uint32{}
-	for cl := 1; cl < len(nextCodes); cl++ {
-		currCode = (currCode + histogram[cl-1]) << 1
-		nextCodes[cl] = currCode
-	}
-	codes := make([]uint32, len(codeLengths))
-	for symbol, cl := range codeLengths {
-		if cl > 0 {
-			codes[symbol] = nextCodes[cl]
-			nextCodes[cl]++
-		}
-	}
-	return codes, nil
-}
-
-// build builds a canonical Huffman tree from the given code lengths.
-func (h *hTree) build(codeLengths []uint32) error {
-	// Calculate the number of symbols.
-	var nSymbols, lastSymbol uint32
-	for symbol, cl := range codeLengths {
-		if cl != 0 {
-			nSymbols++
-			lastSymbol = uint32(symbol)
-		}
-	}
-	if nSymbols == 0 {
-		return errInvalidHuffmanTree
-	}
-	h.nodes = make([]hNode, 1, 2*nSymbols-1)
-	// Handle the trivial case.
-	if nSymbols == 1 {
-		if len(codeLengths) <= int(lastSymbol) {
-			return errInvalidHuffmanTree
-		}
-		return h.insert(lastSymbol, 0, 0)
-	}
-	// Handle the non-trivial case.
-	codes, err := codeLengthsToCodes(codeLengths)
-	if err != nil {
-		return err
-	}
-	for symbol, cl := range codeLengths {
-		if cl > 0 {
-			if err := h.insert(uint32(symbol), codes[symbol], cl); err != nil {
-				return err
-			}
-		}
-	}
-	return nil
-}
-
-// buildSimple builds a Huffman tree with 1 or 2 symbols.
-func (h *hTree) buildSimple(nSymbols uint32, symbols [2]uint32, alphabetSize uint32) error {
-	h.nodes = make([]hNode, 1, 2*nSymbols-1)
-	for i := uint32(0); i < nSymbols; i++ {
-		if symbols[i] >= alphabetSize {
-			return errInvalidHuffmanTree
-		}
-		if err := h.insert(symbols[i], i, nSymbols-1); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-// next returns the next Huffman-encoded symbol from the bit-stream d.
-func (h *hTree) next(d *decoder) (uint32, error) {
-	var n uint32
-	// Read enough bits so that we can use the look-up table.
-	if d.nBits < lutSize {
-		c, err := d.r.ReadByte()
-		if err != nil {
-			if err == io.EOF {
-				// There are no more bytes of data, but we may still be able
-				// to read the next symbol out of the previously read bits.
-				goto slowPath
-			}
-			return 0, err
-		}
-		d.bits |= uint32(c) << d.nBits
-		d.nBits += 8
-	}
-	// Use the look-up table.
-	n = h.lut[d.bits&lutMask]
-	if b := n & 0xff; b != 0 {
-		b--
-		d.bits >>= b
-		d.nBits -= b
-		return n >> 8, nil
-	}
-	n >>= 8
-	d.bits >>= lutSize
-	d.nBits -= lutSize
-
-slowPath:
-	for h.nodes[n].children != leafNode {
-		if d.nBits == 0 {
-			c, err := d.r.ReadByte()
-			if err != nil {
-				if err == io.EOF {
-					err = io.ErrUnexpectedEOF
-				}
-				return 0, err
-			}
-			d.bits = uint32(c)
-			d.nBits = 8
-		}
-		n = uint32(h.nodes[n].children) + 1&d.bits
-		d.bits >>= 1
-		d.nBits--
-	}
-	return h.nodes[n].symbol, nil
-}
diff --git a/vendor/golang.org/x/image/vp8l/transform.go b/vendor/golang.org/x/image/vp8l/transform.go
deleted file mode 100644
index 06543dacb..000000000
--- a/vendor/golang.org/x/image/vp8l/transform.go
+++ /dev/null
@@ -1,299 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package vp8l
-
-// This file deals with image transforms, specified in section 3.
-
-// nTiles returns the number of tiles needed to cover size pixels, where each
-// tile's side is 1<<bits pixels long.
-func nTiles(size int32, bits uint32) int32 {
-	return (size + 1<<bits - 1) >> bits
-}
-
-const (
-	transformTypePredictor     = 0
-	transformTypeCrossColor    = 1
-	transformTypeSubtractGreen = 2
-	transformTypeColorIndexing = 3
-	nTransformTypes            = 4
-)
-
-// transform holds the parameters for an invertible transform.
-type transform struct {
-	// transformType is the type of the transform.
-	transformType uint32
-	// oldWidth is the width of the image before transformation (or
-	// equivalently, after inverse transformation). The color-indexing
-	// transform can reduce the width. For example, a 50-pixel-wide
-	// image that only needs 4 bits (half a byte) per color index can
-	// be transformed into a 25-pixel-wide image.
-	oldWidth int32
-	// bits is the log-2 size of the transform's tiles, for the predictor
-	// and cross-color transforms. 8>>bits is the number of bits per
-	// color index, for the color-index transform.
-	bits uint32
-	// pix is the tile values, for the predictor and cross-color
-	// transforms, and the color palette, for the color-index transform.
-	pix []byte
-}
-
-var inverseTransforms = [nTransformTypes]func(*transform, []byte, int32) []byte{
-	transformTypePredictor:     inversePredictor,
-	transformTypeCrossColor:    inverseCrossColor,
-	transformTypeSubtractGreen: inverseSubtractGreen,
-	transformTypeColorIndexing: inverseColorIndexing,
-}
-
-func inversePredictor(t *transform, pix []byte, h int32) []byte {
-	if t.oldWidth == 0 || h == 0 {
-		return pix
-	}
-	// The first pixel's predictor is mode 0 (opaque black).
-	pix[3] += 0xff
-	p, mask := int32(4), int32(1)<<t.bits-1
-	for x := int32(1); x < t.oldWidth; x++ {
-		// The rest of the first row's predictor is mode 1 (L).
-		pix[p+0] += pix[p-4]
-		pix[p+1] += pix[p-3]
-		pix[p+2] += pix[p-2]
-		pix[p+3] += pix[p-1]
-		p += 4
-	}
-	top, tilesPerRow := 0, nTiles(t.oldWidth, t.bits)
-	for y := int32(1); y < h; y++ {
-		// The first column's predictor is mode 2 (T).
-		pix[p+0] += pix[top+0]
-		pix[p+1] += pix[top+1]
-		pix[p+2] += pix[top+2]
-		pix[p+3] += pix[top+3]
-		p, top = p+4, top+4
-
-		q := 4 * (y >> t.bits) * tilesPerRow
-		predictorMode := t.pix[q+1] & 0x0f
-		q += 4
-		for x := int32(1); x < t.oldWidth; x++ {
-			if x&mask == 0 {
-				predictorMode = t.pix[q+1] & 0x0f
-				q += 4
-			}
-			switch predictorMode {
-			case 0: // Opaque black.
-				pix[p+3] += 0xff
-
-			case 1: // L.
-				pix[p+0] += pix[p-4]
-				pix[p+1] += pix[p-3]
-				pix[p+2] += pix[p-2]
-				pix[p+3] += pix[p-1]
-
-			case 2: // T.
-				pix[p+0] += pix[top+0]
-				pix[p+1] += pix[top+1]
-				pix[p+2] += pix[top+2]
-				pix[p+3] += pix[top+3]
-
-			case 3: // TR.
-				pix[p+0] += pix[top+4]
-				pix[p+1] += pix[top+5]
-				pix[p+2] += pix[top+6]
-				pix[p+3] += pix[top+7]
-
-			case 4: // TL.
-				pix[p+0] += pix[top-4]
-				pix[p+1] += pix[top-3]
-				pix[p+2] += pix[top-2]
-				pix[p+3] += pix[top-1]
-
-			case 5: // Average2(Average2(L, TR), T).
-				pix[p+0] += avg2(avg2(pix[p-4], pix[top+4]), pix[top+0])
-				pix[p+1] += avg2(avg2(pix[p-3], pix[top+5]), pix[top+1])
-				pix[p+2] += avg2(avg2(pix[p-2], pix[top+6]), pix[top+2])
-				pix[p+3] += avg2(avg2(pix[p-1], pix[top+7]), pix[top+3])
-
-			case 6: // Average2(L, TL).
-				pix[p+0] += avg2(pix[p-4], pix[top-4])
-				pix[p+1] += avg2(pix[p-3], pix[top-3])
-				pix[p+2] += avg2(pix[p-2], pix[top-2])
-				pix[p+3] += avg2(pix[p-1], pix[top-1])
-
-			case 7: // Average2(L, T).
-				pix[p+0] += avg2(pix[p-4], pix[top+0])
-				pix[p+1] += avg2(pix[p-3], pix[top+1])
-				pix[p+2] += avg2(pix[p-2], pix[top+2])
-				pix[p+3] += avg2(pix[p-1], pix[top+3])
-
-			case 8: // Average2(TL, T).
-				pix[p+0] += avg2(pix[top-4], pix[top+0])
-				pix[p+1] += avg2(pix[top-3], pix[top+1])
-				pix[p+2] += avg2(pix[top-2], pix[top+2])
-				pix[p+3] += avg2(pix[top-1], pix[top+3])
-
-			case 9: // Average2(T, TR).
-				pix[p+0] += avg2(pix[top+0], pix[top+4])
-				pix[p+1] += avg2(pix[top+1], pix[top+5])
-				pix[p+2] += avg2(pix[top+2], pix[top+6])
-				pix[p+3] += avg2(pix[top+3], pix[top+7])
-
-			case 10: // Average2(Average2(L, TL), Average2(T, TR)).
-				pix[p+0] += avg2(avg2(pix[p-4], pix[top-4]), avg2(pix[top+0], pix[top+4]))
-				pix[p+1] += avg2(avg2(pix[p-3], pix[top-3]), avg2(pix[top+1], pix[top+5]))
-				pix[p+2] += avg2(avg2(pix[p-2], pix[top-2]), avg2(pix[top+2], pix[top+6]))
-				pix[p+3] += avg2(avg2(pix[p-1], pix[top-1]), avg2(pix[top+3], pix[top+7]))
-
-			case 11: // Select(L, T, TL).
-				l0 := int32(pix[p-4])
-				l1 := int32(pix[p-3])
-				l2 := int32(pix[p-2])
-				l3 := int32(pix[p-1])
-				c0 := int32(pix[top-4])
-				c1 := int32(pix[top-3])
-				c2 := int32(pix[top-2])
-				c3 := int32(pix[top-1])
-				t0 := int32(pix[top+0])
-				t1 := int32(pix[top+1])
-				t2 := int32(pix[top+2])
-				t3 := int32(pix[top+3])
-				l := abs(c0-t0) + abs(c1-t1) + abs(c2-t2) + abs(c3-t3)
-				t := abs(c0-l0) + abs(c1-l1) + abs(c2-l2) + abs(c3-l3)
-				if l < t {
-					pix[p+0] += uint8(l0)
-					pix[p+1] += uint8(l1)
-					pix[p+2] += uint8(l2)
-					pix[p+3] += uint8(l3)
-				} else {
-					pix[p+0] += uint8(t0)
-					pix[p+1] += uint8(t1)
-					pix[p+2] += uint8(t2)
-					pix[p+3] += uint8(t3)
-				}
-
-			case 12: // ClampAddSubtractFull(L, T, TL).
-				pix[p+0] += clampAddSubtractFull(pix[p-4], pix[top+0], pix[top-4])
-				pix[p+1] += clampAddSubtractFull(pix[p-3], pix[top+1], pix[top-3])
-				pix[p+2] += clampAddSubtractFull(pix[p-2], pix[top+2], pix[top-2])
-				pix[p+3] += clampAddSubtractFull(pix[p-1], pix[top+3], pix[top-1])
-
-			case 13: // ClampAddSubtractHalf(Average2(L, T), TL).
-				pix[p+0] += clampAddSubtractHalf(avg2(pix[p-4], pix[top+0]), pix[top-4])
-				pix[p+1] += clampAddSubtractHalf(avg2(pix[p-3], pix[top+1]), pix[top-3])
-				pix[p+2] += clampAddSubtractHalf(avg2(pix[p-2], pix[top+2]), pix[top-2])
-				pix[p+3] += clampAddSubtractHalf(avg2(pix[p-1], pix[top+3]), pix[top-1])
-			}
-			p, top = p+4, top+4
-		}
-	}
-	return pix
-}
-
-func inverseCrossColor(t *transform, pix []byte, h int32) []byte {
-	var greenToRed, greenToBlue, redToBlue int32
-	p, mask, tilesPerRow := int32(0), int32(1)<<t.bits-1, nTiles(t.oldWidth, t.bits)
-	for y := int32(0); y < h; y++ {
-		q := 4 * (y >> t.bits) * tilesPerRow
-		for x := int32(0); x < t.oldWidth; x++ {
-			if x&mask == 0 {
-				redToBlue = int32(int8(t.pix[q+0]))
-				greenToBlue = int32(int8(t.pix[q+1]))
-				greenToRed = int32(int8(t.pix[q+2]))
-				q += 4
-			}
-			red := pix[p+0]
-			green := pix[p+1]
-			blue := pix[p+2]
-			red += uint8(uint32(greenToRed*int32(int8(green))) >> 5)
-			blue += uint8(uint32(greenToBlue*int32(int8(green))) >> 5)
-			blue += uint8(uint32(redToBlue*int32(int8(red))) >> 5)
-			pix[p+0] = red
-			pix[p+2] = blue
-			p += 4
-		}
-	}
-	return pix
-}
-
-func inverseSubtractGreen(t *transform, pix []byte, h int32) []byte {
-	for p := 0; p < len(pix); p += 4 {
-		green := pix[p+1]
-		pix[p+0] += green
-		pix[p+2] += green
-	}
-	return pix
-}
-
-func inverseColorIndexing(t *transform, pix []byte, h int32) []byte {
-	if t.bits == 0 {
-		for p := 0; p < len(pix); p += 4 {
-			i := 4 * uint32(pix[p+1])
-			pix[p+0] = t.pix[i+0]
-			pix[p+1] = t.pix[i+1]
-			pix[p+2] = t.pix[i+2]
-			pix[p+3] = t.pix[i+3]
-		}
-		return pix
-	}
-
-	vMask, xMask, bitsPerPixel := uint32(0), int32(0), uint32(8>>t.bits)
-	switch t.bits {
-	case 1:
-		vMask, xMask = 0x0f, 0x01
-	case 2:
-		vMask, xMask = 0x03, 0x03
-	case 3:
-		vMask, xMask = 0x01, 0x07
-	}
-
-	d, p, v, dst := 0, 0, uint32(0), make([]byte, 4*t.oldWidth*h)
-	for y := int32(0); y < h; y++ {
-		for x := int32(0); x < t.oldWidth; x++ {
-			if x&xMask == 0 {
-				v = uint32(pix[p+1])
-				p += 4
-			}
-
-			i := 4 * (v & vMask)
-			dst[d+0] = t.pix[i+0]
-			dst[d+1] = t.pix[i+1]
-			dst[d+2] = t.pix[i+2]
-			dst[d+3] = t.pix[i+3]
-			d += 4
-
-			v >>= bitsPerPixel
-		}
-	}
-	return dst
-}
-
-func abs(x int32) int32 {
-	if x < 0 {
-		return -x
-	}
-	return x
-}
-
-func avg2(a, b uint8) uint8 {
-	return uint8((int32(a) + int32(b)) / 2)
-}
-
-func clampAddSubtractFull(a, b, c uint8) uint8 {
-	x := int32(a) + int32(b) - int32(c)
-	if x < 0 {
-		return 0
-	}
-	if x > 255 {
-		return 255
-	}
-	return uint8(x)
-}
-
-func clampAddSubtractHalf(a, b uint8) uint8 {
-	x := int32(a) + (int32(a)-int32(b))/2
-	if x < 0 {
-		return 0
-	}
-	if x > 255 {
-		return 255
-	}
-	return uint8(x)
-}
diff --git a/vendor/golang.org/x/image/webp/decode.go b/vendor/golang.org/x/image/webp/decode.go
deleted file mode 100644
index e211c7d57..000000000
--- a/vendor/golang.org/x/image/webp/decode.go
+++ /dev/null
@@ -1,276 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package webp
-
-import (
-	"bytes"
-	"errors"
-	"image"
-	"image/color"
-	"io"
-
-	"golang.org/x/image/riff"
-	"golang.org/x/image/vp8"
-	"golang.org/x/image/vp8l"
-)
-
-var errInvalidFormat = errors.New("webp: invalid format")
-
-var (
-	fccALPH = riff.FourCC{'A', 'L', 'P', 'H'}
-	fccVP8  = riff.FourCC{'V', 'P', '8', ' '}
-	fccVP8L = riff.FourCC{'V', 'P', '8', 'L'}
-	fccVP8X = riff.FourCC{'V', 'P', '8', 'X'}
-	fccWEBP = riff.FourCC{'W', 'E', 'B', 'P'}
-)
-
-func decode(r io.Reader, configOnly bool) (image.Image, image.Config, error) {
-	formType, riffReader, err := riff.NewReader(r)
-	if err != nil {
-		return nil, image.Config{}, err
-	}
-	if formType != fccWEBP {
-		return nil, image.Config{}, errInvalidFormat
-	}
-
-	var (
-		alpha          []byte
-		alphaStride    int
-		wantAlpha      bool
-		seenVP8X       bool
-		widthMinusOne  uint32
-		heightMinusOne uint32
-		buf            [10]byte
-	)
-	for {
-		chunkID, chunkLen, chunkData, err := riffReader.Next()
-		if err == io.EOF {
-			err = errInvalidFormat
-		}
-		if err != nil {
-			return nil, image.Config{}, err
-		}
-
-		switch chunkID {
-		case fccALPH:
-			if !wantAlpha {
-				return nil, image.Config{}, errInvalidFormat
-			}
-			wantAlpha = false
-			// Read the Pre-processing | Filter | Compression byte.
-			if _, err := io.ReadFull(chunkData, buf[:1]); err != nil {
-				if err == io.EOF {
-					err = errInvalidFormat
-				}
-				return nil, image.Config{}, err
-			}
-			alpha, alphaStride, err = readAlpha(chunkData, widthMinusOne, heightMinusOne, buf[0]&0x03)
-			if err != nil {
-				return nil, image.Config{}, err
-			}
-			unfilterAlpha(alpha, alphaStride, (buf[0]>>2)&0x03)
-
-		case fccVP8:
-			if wantAlpha || int32(chunkLen) < 0 {
-				return nil, image.Config{}, errInvalidFormat
-			}
-			d := vp8.NewDecoder()
-			d.Init(chunkData, int(chunkLen))
-			fh, err := d.DecodeFrameHeader()
-			if err != nil {
-				return nil, image.Config{}, err
-			}
-			if configOnly {
-				return nil, image.Config{
-					ColorModel: color.YCbCrModel,
-					Width:      fh.Width,
-					Height:     fh.Height,
-				}, nil
-			}
-			m, err := d.DecodeFrame()
-			if err != nil {
-				return nil, image.Config{}, err
-			}
-			if alpha != nil {
-				return &image.NYCbCrA{
-					YCbCr:   *m,
-					A:       alpha,
-					AStride: alphaStride,
-				}, image.Config{}, nil
-			}
-			return m, image.Config{}, nil
-
-		case fccVP8L:
-			if wantAlpha || alpha != nil {
-				return nil, image.Config{}, errInvalidFormat
-			}
-			if configOnly {
-				c, err := vp8l.DecodeConfig(chunkData)
-				return nil, c, err
-			}
-			m, err := vp8l.Decode(chunkData)
-			return m, image.Config{}, err
-
-		case fccVP8X:
-			if seenVP8X {
-				return nil, image.Config{}, errInvalidFormat
-			}
-			seenVP8X = true
-			if chunkLen != 10 {
-				return nil, image.Config{}, errInvalidFormat
-			}
-			if _, err := io.ReadFull(chunkData, buf[:10]); err != nil {
-				return nil, image.Config{}, err
-			}
-			const (
-				animationBit    = 1 << 1
-				xmpMetadataBit  = 1 << 2
-				exifMetadataBit = 1 << 3
-				alphaBit        = 1 << 4
-				iccProfileBit   = 1 << 5
-			)
-			wantAlpha = (buf[0] & alphaBit) != 0
-			widthMinusOne = uint32(buf[4]) | uint32(buf[5])<<8 | uint32(buf[6])<<16
-			heightMinusOne = uint32(buf[7]) | uint32(buf[8])<<8 | uint32(buf[9])<<16
-			if configOnly {
-				if wantAlpha {
-					return nil, image.Config{
-						ColorModel: color.NYCbCrAModel,
-						Width:      int(widthMinusOne) + 1,
-						Height:     int(heightMinusOne) + 1,
-					}, nil
-				}
-				return nil, image.Config{
-					ColorModel: color.YCbCrModel,
-					Width:      int(widthMinusOne) + 1,
-					Height:     int(heightMinusOne) + 1,
-				}, nil
-			}
-		}
-	}
-}
-
-func readAlpha(chunkData io.Reader, widthMinusOne, heightMinusOne uint32, compression byte) (
-	alpha []byte, alphaStride int, err error) {
-
-	switch compression {
-	case 0:
-		w := int(widthMinusOne) + 1
-		h := int(heightMinusOne) + 1
-		alpha = make([]byte, w*h)
-		if _, err := io.ReadFull(chunkData, alpha); err != nil {
-			return nil, 0, err
-		}
-		return alpha, w, nil
-
-	case 1:
-		// Read the VP8L-compressed alpha values. First, synthesize a 5-byte VP8L header:
-		// a 1-byte magic number, a 14-bit widthMinusOne, a 14-bit heightMinusOne,
-		// a 1-bit (ignored, zero) alphaIsUsed and a 3-bit (zero) version.
-		// TODO(nigeltao): be more efficient than decoding an *image.NRGBA just to
-		// extract the green values to a separately allocated []byte. Fixing this
-		// will require changes to the vp8l package's API.
-		if widthMinusOne > 0x3fff || heightMinusOne > 0x3fff {
-			return nil, 0, errors.New("webp: invalid format")
-		}
-		alphaImage, err := vp8l.Decode(io.MultiReader(
-			bytes.NewReader([]byte{
-				0x2f, // VP8L magic number.
-				uint8(widthMinusOne),
-				uint8(widthMinusOne>>8) | uint8(heightMinusOne<<6),
-				uint8(heightMinusOne >> 2),
-				uint8(heightMinusOne >> 10),
-			}),
-			chunkData,
-		))
-		if err != nil {
-			return nil, 0, err
-		}
-		// The green values of the inner NRGBA image are the alpha values of the
-		// outer NYCbCrA image.
-		pix := alphaImage.(*image.NRGBA).Pix
-		alpha = make([]byte, len(pix)/4)
-		for i := range alpha {
-			alpha[i] = pix[4*i+1]
-		}
-		return alpha, int(widthMinusOne) + 1, nil
-	}
-	return nil, 0, errInvalidFormat
-}
-
-func unfilterAlpha(alpha []byte, alphaStride int, filter byte) {
-	if len(alpha) == 0 || alphaStride == 0 {
-		return
-	}
-	switch filter {
-	case 1: // Horizontal filter.
-		for i := 1; i < alphaStride; i++ {
-			alpha[i] += alpha[i-1]
-		}
-		for i := alphaStride; i < len(alpha); i += alphaStride {
-			// The first column is equivalent to the vertical filter.
-			alpha[i] += alpha[i-alphaStride]
-
-			for j := 1; j < alphaStride; j++ {
-				alpha[i+j] += alpha[i+j-1]
-			}
-		}
-
-	case 2: // Vertical filter.
-		// The first row is equivalent to the horizontal filter.
-		for i := 1; i < alphaStride; i++ {
-			alpha[i] += alpha[i-1]
-		}
-
-		for i := alphaStride; i < len(alpha); i++ {
-			alpha[i] += alpha[i-alphaStride]
-		}
-
-	case 3: // Gradient filter.
-		// The first row is equivalent to the horizontal filter.
-		for i := 1; i < alphaStride; i++ {
-			alpha[i] += alpha[i-1]
-		}
-
-		for i := alphaStride; i < len(alpha); i += alphaStride {
-			// The first column is equivalent to the vertical filter.
-			alpha[i] += alpha[i-alphaStride]
-
-			// The interior is predicted on the three top/left pixels.
-			for j := 1; j < alphaStride; j++ {
-				c := int(alpha[i+j-alphaStride-1])
-				b := int(alpha[i+j-alphaStride])
-				a := int(alpha[i+j-1])
-				x := a + b - c
-				if x < 0 {
-					x = 0
-				} else if x > 255 {
-					x = 255
-				}
-				alpha[i+j] += uint8(x)
-			}
-		}
-	}
-}
-
-// Decode reads a WEBP image from r and returns it as an image.Image.
-func Decode(r io.Reader) (image.Image, error) {
-	m, _, err := decode(r, false)
-	if err != nil {
-		return nil, err
-	}
-	return m, err
-}
-
-// DecodeConfig returns the color model and dimensions of a WEBP image without
-// decoding the entire image.
-func DecodeConfig(r io.Reader) (image.Config, error) {
-	_, c, err := decode(r, true)
-	return c, err
-}
-
-func init() {
-	image.RegisterFormat("webp", "RIFF????WEBPVP8", Decode, DecodeConfig)
-}
diff --git a/vendor/golang.org/x/image/webp/doc.go b/vendor/golang.org/x/image/webp/doc.go
deleted file mode 100644
index e321c8542..000000000
--- a/vendor/golang.org/x/image/webp/doc.go
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright 2016 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package webp implements a decoder for WEBP images.
-//
-// WEBP is defined at:
-// https://developers.google.com/speed/webp/docs/riff_container
-package webp // import "golang.org/x/image/webp"