libwebp: upstream animation cherry-picks

third_party/libwebp/webp/mux.h

Index: third_party/libwebp/webp/mux.h
diff --git a/third_party/libwebp/webp/mux.h b/third_party/libwebp/webp/mux.h
index b8c7dc62ec526fdf1daedc4bd96472b3755117a9..cd5665053d0bd3c0e6c84913c7dfedb1beae2bf6 100644
--- a/third_party/libwebp/webp/mux.h
+++ b/third_party/libwebp/webp/mux.h
@@ -199,7 +199,8 @@ struct WebPMuxFrameInfo {
   WebPChunkId id;         // frame type: should be one of WEBP_CHUNK_ANMF,
                           // WEBP_CHUNK_FRGM or WEBP_CHUNK_IMAGE
   WebPMuxAnimDispose dispose_method;  // Disposal method for the frame.
-  uint32_t    pad[2];     // padding for later use
+  WebPMuxAnimBlend   blend_method;    // Blend operation for the frame.

[fbarchard, 2013/08/21 02:00:13]

Is WebPMuxAnimBlend   blend_method; a full int?

[urvang (Google), 2013/08/21 02:16:51]

I guess the question comes from the fact that we decremented padding size by 1.

IIRC, the size of WebPMuxAnimBlend is not guaranteed to be that of an int (as 1
byte can hold it too), but most implementations would make the size to be that
of an int.

+  uint32_t    pad[1];     // padding for later use
 };
 
 // Sets the (non-animated and non-fragmented) image in the mux object.