DO NOT COMMIT: Experimental removal of encoded image data

third_party/WebKit/Source/platform/graphics/BitmapImage.cpp

 /*
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2008 Apple 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 100 matching lines @@
 
 void BitmapImage::destroyDecodedData()
 {
     m_cachedFrame.reset();
     for (size_t i = 0; i < m_frames.size(); ++i)
         m_frames[i].clear(true);
     m_source.clearCacheExceptFrame(kNotFound);
     notifyMemoryChanged();
 }
 
+bool BitmapImage::clear()
+{
+    destroyDecodedData();
+    return m_source.clear();
+}
+
 PassRefPtr<SharedBuffer> BitmapImage::data()
 {
     return m_source.data();
 }
 
 void BitmapImage::notifyMemoryChanged()
 {
     if (getImageObserver())
         getImageObserver()->decodedSizeChangedTo(this, totalFrameBytes());
 }
@@ skipping 206 matching lines @@
 }
 
 sk_sp<SkImage> BitmapImage::frameAtIndex(size_t index)
 {
     if (index >= frameCount())
         return nullptr;
 
     if (index == m_cachedFrameIndex && m_cachedFrame)
         return m_cachedFrame;
 
+    if (m_source.isBufferCleared()) {
+        getImageObserver()->requireReloading(this);
+        return nullptr;
+    }
+
     return decodeAndCacheFrame(index);
 }
 
 bool BitmapImage::frameIsCompleteAtIndex(size_t index)
 {
     if (index < m_frames.size() && m_frames[index].m_haveMetadata && m_frames[index].m_isComplete)
         return true;
 
     return m_source.frameIsCompleteAtIndex(index);
 }
@@ skipping 278 matching lines @@
 
     return true;
 }
 
 void BitmapImage::notifyObserversOfAnimationAdvance(TimerBase*)
 {
     getImageObserver()->animationAdvanced(this);
 }
 
 } // namespace blink