Add SkWebpCodec, for decoding .webp images.

src/codec/SkCodec.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCodec.h"
 #include "SkData.h"
 #include "SkCodec_libbmp.h"
 #include "SkCodec_libgif.h"
 #include "SkCodec_libico.h"
 #include "SkCodec_libpng.h"
 #include "SkCodec_wbmp.h"
 #include "SkCodecPriv.h"
 #include "SkStream.h"
+#include "SkWebpCodec.h"
 
 struct DecoderProc {
     bool (*IsFormat)(SkStream*);
     SkCodec* (*NewFromStream)(SkStream*);
 };
 
 static const DecoderProc gDecoderProcs[] = {
     { SkPngCodec::IsPng, SkPngCodec::NewFromStream },
+    { SkWebpCodec::IsWebp, SkWebpCodec::NewFromStream },
     { SkGifCodec::IsGif, SkGifCodec::NewFromStream },
     { SkIcoCodec::IsIco, SkIcoCodec::NewFromStream },
     { SkBmpCodec::IsBmp, SkBmpCodec::NewFromStream },
     { SkWbmpCodec::IsWbmp, SkWbmpCodec::NewFromStream }
 };
 
 SkCodec* SkCodec::NewFromStream(SkStream* stream) {
     if (!stream) {
         return NULL;
     }
@@ skipping 49 matching lines @@
         return kNoRewindNecessary_RewindState;
     }
     return fStream->rewind() ? kRewound_RewindState
                              : kCouldNotRewind_RewindState;
 }
 
 SkScanlineDecoder* SkCodec::getScanlineDecoder(const SkImageInfo& dstInfo) {
     fScanlineDecoder.reset(this->onGetScanlineDecoder(dstInfo));
     return fScanlineDecoder.get();
 }