Make Image::image_observer_ WeakPersistent

third_party/WebKit/Source/core/svg/graphics/SVGImageChromeClient.cpp

 /*
  * Copyright (C) 2012 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 99 matching lines @@
 
 void SVGImageChromeClient::AnimationTimerFired(TimerBase*) {
   if (!image_)
     return;
 
   // The SVGImageChromeClient object's lifetime is dependent on
   // the ImageObserver (an ImageResourceContent) of its image. Should it
   // be dead and about to be lazily swept out, do not proceed.
   //
   // TODO(Oilpan): move (SVG)Image to the Oilpan heap, and avoid
   // this explicit lifetime check.

[haraken, 2017/05/25 23:23:02]

Is it still hard to move Image to Oilpan's heap?

[hiroshige, 2017/05/26 00:03:27]

I'm not sure. Were there any blocking issues to move Image to Oilpan heap?

(Related issue: Issue 719617 about thread affinity of Image)

-  if (ThreadHeap::WillObjectBeLazilySwept(image_->GetImageObserver()))
+  if (image_->GetImageObserver() &&
+      ThreadHeap::WillObjectBeLazilySwept(image_->GetImageObserver()))

[haraken, 2017/05/25 23:23:02]

Now that Image::image_observer_ is cleared in the stop-the-world phase, we can
remove the WillObjectBeLazilySwept check.

+Sigbjorn for double-checking.

[hiroshige, 2017/05/26 18:44:58]

Done.

     return;
 
   image_->ServiceAnimations(MonotonicallyIncreasingTime());
 }
 
 }  // namespace blink