[BitmapImage] Don't destroy lazy-decoded frames

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 121 matching lines @@
 
     destroyMetadataAndNotify(m_source.clearCacheExceptFrame(destroyAll ? kNotFound : m_currentFrame));
 }
 
 void BitmapImage::destroyDecodedDataIfNecessary()
 {
     // Animated images >5MB are considered large enough that we'll only hang on
     // to one frame at a time.
     static const size_t cLargeAnimationCutoff = 5242880;
     size_t allFrameBytes = 0;
-    for (size_t i = 0; i < m_frames.size(); ++i)
+    for (size_t i = 0; i < m_frames.size(); ++i) {
+        // The memory for lazy-decoded frames is managed externally.
+        if (m_frames[i].m_frame && m_frames[i].m_frame->isLazyGenerated()) {
+            // We don't mix lazy/non-lazy frames.
+            ASSERT(!allFrameBytes);
+            break;
+        }
+
         allFrameBytes += m_frames[i].m_frameBytes;
+    }
 
     if (allFrameBytes > cLargeAnimationCutoff) {
         destroyDecodedData(false);
     }
 }
 
 void BitmapImage::destroyMetadataAndNotify(size_t frameBytesCleared)
 {
     if (frameBytesCleared && imageObserver())
         imageObserver()->decodedSizeChanged(this, -safeCast<int>(frameBytesCleared));
@@ skipping 509 matching lines @@
     destroyDecodedDataIfNecessary();
 
     // We need to draw this frame if we advanced to it while not skipping, or if
     // while trying to skip frames we hit the last frame and thus had to stop.
     if (skippingFrames != advancedAnimation)
         imageObserver()->animationAdvanced(this);
     return advancedAnimation;
 }
 
 } // namespace blink