Remove redundant reading and writing of data about SharedBuffer.

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

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
  *     documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 #ifndef DecodingImageGenerator_h
 #define DecodingImageGenerator_h
 
 #include "platform/PlatformExport.h"
+#include "platform/SharedBuffer.h"
 #include "platform/image-decoders/SegmentReader.h"
 #include "platform/wtf/Allocator.h"
 #include "platform/wtf/Noncopyable.h"
 #include "platform/wtf/PassRefPtr.h"
 #include "platform/wtf/RefPtr.h"
 #include "third_party/skia/include/core/SkImageGenerator.h"
 #include "third_party/skia/include/core/SkImageInfo.h"
 
 class SkData;
 
@@ skipping 13 matching lines @@
   enum { kNeedNewImageUniqueID = SkImageGenerator::kNeedNewImageUniqueID };
 
   static SkImageGenerator* Create(SkData*);
 
   DecodingImageGenerator(PassRefPtr<ImageFrameGenerator>,
                          const SkImageInfo&,
                          PassRefPtr<SegmentReader>,
                          bool all_data_received,
                          size_t index,
                          uint32_t unique_id = kNeedNewImageUniqueID);
+
+  DecodingImageGenerator(PassRefPtr<ImageFrameGenerator>,
+                         const SkImageInfo&,
+                         PassRefPtr<SharedBuffer::ThreadSafeStepper>,
+                         bool all_data_received,
+                         size_t index,
+                         uint32_t unique_id = kNeedNewImageUniqueID);
+
   ~DecodingImageGenerator() override;
 
   void SetCanYUVDecode(bool yes) { can_yuv_decode_ = yes; }
 
  protected:
   SkData* onRefEncodedData() override;
 
   bool onGetPixels(const SkImageInfo&,
                    void* pixels,
                    size_t row_bytes,
                    const Options&) override;
 
   bool onQueryYUV8(SkYUVSizeInfo*, SkYUVColorSpace*) const override;
 
   bool onGetYUV8Planes(const SkYUVSizeInfo&, void* planes[3]) override;
 
  private:
+  PassRefPtr<SegmentReader> encoded_data() const;
+
   RefPtr<ImageFrameGenerator> frame_generator_;
-  const RefPtr<SegmentReader> data_;  // Data source.
+  const RefPtr<SegmentReader> reader_;
+  const RefPtr<SharedBuffer::ThreadSafeStepper> stepper_;
   const bool all_data_received_;
   const size_t frame_index_;
   bool can_yuv_decode_;
 };
 
 }  // namespace blink
 
 #endif  // DecodingImageGenerator_h_