Use the upstream version of libwebp, v0.4.3.

src/codec/SkWebpCodec.cpp

Index: src/codec/SkWebpCodec.cpp
diff --git a/src/codec/SkWebpCodec.cpp b/src/codec/SkWebpCodec.cpp
index b02015c7a7684ca10ae9ce802762c104feab954a..7299d14cc248a2b8546c9de993e9fe2cfd3c1e22 100644
--- a/src/codec/SkWebpCodec.cpp
+++ b/src/codec/SkWebpCodec.cpp
@@ -18,6 +18,7 @@
 // If moving libwebp out of skia source tree, path for webp headers must be
 // updated accordingly. Here, we enforce using local copy in webp sub-directory.
 #include "webp/decode.h"
+#include "webp/demux.h"
 #include "webp/encode.h"
 
 bool SkWebpCodec::IsWebp(SkStream* stream) {
@@ -43,15 +44,31 @@ static bool webp_parse_header(SkStream* stream, SkImageInfo* info) {
         return false;
     }
 
-    WebPBitstreamFeatures features;
-    VP8StatusCode status = WebPGetFeatures(buffer, WEBP_VP8_HEADER_SIZE, &features);
-    if (VP8_STATUS_OK != status) {
-        return false; // Invalid WebP file.
+    WebPData demuxData = { buffer, WEBP_VP8_HEADER_SIZE };
+    WebPDemuxState demuxState;
+    WebPDemuxer* demuxer = WebPDemuxPartial(&demuxData, &demuxState);
+    if (!demuxer) {
+        return false;
     }
 
+    SkAutoTCallVProc<WebPDemuxer, WebPDemuxDelete> autoDeleter(demuxer);
+    switch (demuxState) {
+        case WEBP_DEMUX_PARSE_ERROR:
+        case WEBP_DEMUX_PARSING_HEADER:
+            return false;
+        default:
+            // Header parsed.
+            break;
+    }
+
+    uint32_t width = WebPDemuxGetI(demuxer, WEBP_FF_CANVAS_WIDTH);
+    uint32_t height = WebPDemuxGetI(demuxer, WEBP_FF_CANVAS_HEIGHT);
+    uint32_t formatFlags = WebPDemuxGetI(demuxer, WEBP_FF_FORMAT_FLAGS);
+    bool hasAlpha = SkToBool(formatFlags & ALPHA_FLAG) ? 1 : 0;

[msarett, 2015/06/19 12:07:46]

Can this be simpler?
bool hasAlpha = SkToBool(formatFlags & ALPHA_FLAG);

[scroggo, 2015/06/19 18:59:58]

Lol yes. This was copied from SkImageDecoder_libwebp, where hasAlpha is an int
instead of a bool.

+
     // sanity check for image size that's about to be decoded.
     {
-        const int64_t size = sk_64_mul(features.width, features.height);
+        const int64_t size = sk_64_mul(width, height);
         if (!sk_64_isS32(size)) {
             return false;
         }
@@ -66,9 +83,9 @@ static bool webp_parse_header(SkStream* stream, SkImageInfo* info) {
         // Is unpremul the right type? Clients of SkImageGenerator may assume it's the
         // best type, when Skia currently cannot draw unpremul (and raster is faster
         // with premul).
-        *info = SkImageInfo::Make(features.width, features.height, kN32_SkColorType,
-                                  SkToBool(features.has_alpha) ? kUnpremul_SkAlphaType
-                                                              : kOpaque_SkAlphaType);
+        *info = SkImageInfo::Make(width, height, kN32_SkColorType,
+                                  hasAlpha ? kUnpremul_SkAlphaType
+                                           : kOpaque_SkAlphaType);
     }
     return true;
 }