Add support for Animated PNG

third_party/WebKit/Source/platform/image-decoders/webp/WEBPImageDecoder.cpp

Index: third_party/WebKit/Source/platform/image-decoders/webp/WEBPImageDecoder.cpp
diff --git a/third_party/WebKit/Source/platform/image-decoders/webp/WEBPImageDecoder.cpp b/third_party/WebKit/Source/platform/image-decoders/webp/WEBPImageDecoder.cpp
index c9045baf3561de6a1fa4434701bbc638bda8cf33..110f60ee8e8112aeb03b1faaea8477ba4658f52e 100644
--- a/third_party/WebKit/Source/platform/image-decoders/webp/WEBPImageDecoder.cpp
+++ b/third_party/WebKit/Source/platform/image-decoders/webp/WEBPImageDecoder.cpp
@@ -237,7 +237,7 @@ bool WEBPImageDecoder::updateDemuxer() {
   return true;
 }
 
-void WEBPImageDecoder::onInitFrameBuffer(size_t frameIndex) {
+bool WEBPImageDecoder::onInitFrameBuffer(size_t frameIndex) {
   // ImageDecoder::initFrameBuffer does a DCHECK if |frameIndex| exists.
   ImageFrame& buffer = m_frameBufferCache[frameIndex];
 
@@ -257,6 +257,7 @@ void WEBPImageDecoder::onInitFrameBuffer(size_t frameIndex) {
   // loading. The correct alpha value for the frame will be set when it is fully
   // decoded.
   buffer.setHasAlpha(true);
+  return true;
 }
 
 bool WEBPImageDecoder::canReusePreviousFrameBuffer(size_t frameIndex) const {