Eliminate copies of encoded image data

third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.h

Index: third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.h
diff --git a/third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.h b/third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.h
index 3338d4aa8ad1e5039efc98d14e95b2c39d9237ad..332fb7e987ae352e2b1fc9fd107a0f642e271e02 100644
--- a/third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.h
+++ b/third_party/WebKit/Source/platform/graphics/DeferredImageDecoder.h
@@ -31,6 +31,7 @@
 #include "platform/image-decoders/ImageDecoder.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "third_party/skia/include/core/SkPixelRef.h"
+#include "third_party/skia/src/core/SkRWBuffer.h"
 #include "wtf/Allocator.h"
 #include "wtf/Forward.h"
 #include "wtf/OwnPtr.h"
@@ -88,9 +89,10 @@ private:
 
     PassRefPtr<SkImage> createFrameImageAtIndex(size_t index, bool knownToBeOpaque) const;
 
-    RefPtr<SharedBuffer> m_data;
+    // Copy of the data that is passed in, used by deferred decoding.
+    // Allows snapping readonly readers off to use in another thread.

[Peter Kasting, 2016/03/23 02:42:58]

"snapping"?

[scroggo_chromium, 2016/03/24 13:59:45]

I'll update the comment. FWIW, I meant "snapping" as in "snapshot" - the reader
can only read up to the data that had been received when it was created.

+    OwnPtr<SkRWBuffer> m_rwBuffer;
     bool m_allDataReceived;
-    unsigned m_lastDataSize;
     OwnPtr<ImageDecoder> m_actualDecoder;
 
     String m_filenameExtension;