Remove multi-frame image decoder when the image is completely decoded

Source/platform/graphics/test/MockImageDecoder.h

 /*
  * Copyright (C) 2012 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
@@ skipping 51 matching lines @@
     }
 
     virtual IntSize decodedSize() const override
     {
         return m_client->decodedSize().isEmpty() ? size() : m_client->decodedSize();
     }
 
     virtual bool setSize(unsigned width, unsigned height) override
     {
         ImageDecoder::setSize(width, height);
-        m_frameBufferCache.resize(1);
-        m_frameBufferCache[0].setSize(width, height);
+        m_frameBufferCache.resize(m_client->frameCount());
+        for (size_t index = 0; index < m_client->frameCount(); ++index)
+            m_frameBufferCache[index].setSize(width, height);
         return true;
     }
 
     virtual String filenameExtension() const override
     {
         return "mock";
     }
 
     virtual size_t frameCount() override
     {
         return m_client->frameCount();
     }
 
     virtual int repetitionCount() const override
     {
         return m_client->repetitionCount();
     }
 
-    virtual ImageFrame* frameBufferAtIndex(size_t) override
+    virtual ImageFrame* frameBufferAtIndex(size_t index) override
     {
         m_client->frameBufferRequested();
 
-        m_frameBufferCache[0].setStatus(m_client->status());
-        return &m_frameBufferCache[0];
+        m_frameBufferCache[index].setStatus(m_client->status());
+        return &m_frameBufferCache[index];
     }
 
     virtual bool frameIsCompleteAtIndex(size_t) const override
     {
         return m_client->status() == ImageFrame::FrameComplete;
     }
 
     virtual float frameDurationAtIndex(size_t) const override
     {
         return m_client->frameDuration();
     }
 
-    void setFrameHasAlpha(bool hasAlpha) { m_frameBufferCache[0].setHasAlpha(hasAlpha); }
+    void setFrameHasAlpha(bool hasAlpha)
+    {
+        for (size_t index = 0; index < m_client->frameCount(); ++index)
+            m_frameBufferCache[index].setHasAlpha(hasAlpha);
+    }
+
+    virtual size_t clearCacheExceptFrame(size_t) override { return 0; }
 
 private:
     MockImageDecoderClient* m_client;
 };
 
 class MockImageDecoderFactory : public ImageDecoderFactory {
 public:
     static PassOwnPtr<MockImageDecoderFactory> create(MockImageDecoderClient* client, const SkISize& decodedSize)
     {
         return adoptPtr(new MockImageDecoderFactory(client, IntSize(decodedSize.width(), decodedSize.height())));
@@ skipping 19 matching lines @@
     {
     }
 
     MockImageDecoderClient* m_client;
     IntSize m_decodedSize;
 };
 
 } // namespace blink
 
 #endif // MockImageDecoder_h