Add support for encoding/decoding WebP images.

blimp/common/compositor/webp_decoder.h

Index: blimp/common/compositor/webp_decoder.h
diff --git a/blimp/common/compositor/webp_decoder.h b/blimp/common/compositor/webp_decoder.h
new file mode 100644
index 0000000000000000000000000000000000000000..843db94874dbe151c6a4339f900e8186b9e6e4ef
--- /dev/null
+++ b/blimp/common/compositor/webp_decoder.h
@@ -0,0 +1,25 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BLIMP_COMMON_COMPOSITOR_WEBP_DECODER_H_
+#define BLIMP_COMMON_COMPOSITOR_WEBP_DECODER_H_
+
+#include <stddef.h>
+
+#include "blimp/common/blimp_common_export.h"
+#include "third_party/skia/include/core/SkData.h"
+
+class SkBitmap;
+
+namespace blimp {
+
+// WebPDecoder is an implementation of SkPicture::InstallPixelRefProc which
+// is used by the client to decode WebP images that are part of an SkPicture.
+BLIMP_COMMON_EXPORT bool WebPDecoder(const void* input,
+                                     size_t input_size,
+                                     SkBitmap* bitmap);
+
+}  // namespace blimp
+
+#endif  // BLIMP_COMMON_COMPOSITOR_WEBP_DECODER_H_