Eliminate copies of encoded image data

third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h

Index: third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h
diff --git a/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h b/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h
index 2ebd7797caf99844abc34018d95e42f885f8b453..cb0d9250b7f3b9d708a939849548ccb50631a5d0 100644
--- a/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h
+++ b/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h
@@ -29,10 +29,10 @@
 
 #include "SkColorPriv.h"
 #include "platform/PlatformExport.h"
-#include "platform/SharedBuffer.h"
 #include "platform/graphics/ImageOrientation.h"
 #include "platform/image-decoders/ImageAnimation.h"
 #include "platform/image-decoders/ImageFrame.h"
+#include "platform/image-decoders/SegmentReader.h"
 #include "public/platform/Platform.h"
 #include "wtf/Assertions.h"
 #include "wtf/PassOwnPtr.h"
@@ -99,13 +99,13 @@ public:
     // we can't sniff a supported type from the provided data (possibly
     // because there isn't enough data yet).
     // Sets m_maxDecodedBytes to Platform::maxImageDecodedBytes().
-    static PassOwnPtr<ImageDecoder> create(const SharedBuffer& data, AlphaOption, GammaAndColorProfileOption);
+    static PassOwnPtr<ImageDecoder> create(const SegmentReader& data, AlphaOption, GammaAndColorProfileOption);
 
     virtual String filenameExtension() const = 0;
 
     bool isAllDataReceived() const { return m_isAllDataReceived; }
 
-    void setData(SharedBuffer* data, bool allDataReceived)
+    void setData(SegmentReader* data, bool allDataReceived)

[Peter Kasting, 2016/03/23 02:42:59]

This takes ownership from the caller.  It should either be passed via PassRefPtr
or by value with the caller doing std::move(), whichever way common WebKit style
is these days.  (Chromium style would be the latter.)

[f(malita), 2016/03/23 16:41:58]

+1

Not new to this CL, but setData should take a PassRefPtr<SegmentReader>.

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

Since my CL did not introduce this pattern, do you mind if I leave that until a
follow-on?

[f(malita), 2016/03/24 16:48:37]

Yeah, we should do that separately.

     {
         if (m_failed)
             return;
@@ -114,7 +114,7 @@ public:
         onSetData(data);
     }
 
-    virtual void onSetData(SharedBuffer* data) { }
+    virtual void onSetData(SegmentReader* data) { }
 
     bool isSizeAvailable()
     {
@@ -334,7 +334,7 @@ protected:
     // Decodes the requested frame.
     virtual void decode(size_t) = 0;
 
-    RefPtr<SharedBuffer> m_data; // The encoded data.
+    RefPtr<SegmentReader> m_data; // The encoded data.
     Vector<ImageFrame, 1> m_frameBufferCache;
     bool m_premultiplyAlpha;
     bool m_ignoreGammaAndColorProfile;