Add null checks of GetImageObserver() in BitmapImage

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 586 matching lines @@
 
 void BitmapImage::AdvanceAnimationWithoutCatchUp(TimerBase*) {
   if (InternalAdvanceAnimation())
     StartAnimation(kDoNotCatchUp);
 }
 
 bool BitmapImage::InternalAdvanceAnimation(AnimationAdvancement advancement) {
   // Stop the animation.
   StopAnimation();
 
+  if (!GetImageObserver())
+    return false;
+
   // See if anyone is still paying attention to this animation.  If not, we
   // don't advance, and will remain suspended at the current frame until the
   // animation is resumed.
   if (advancement != kSkipFramesToCatchUp &&
       GetImageObserver()->ShouldPauseAnimation(this))
     return false;
 
   if (current_frame_ + 1 < FrameCount()) {
     current_frame_++;
   } else {
@@ skipping 30 matching lines @@
   }
 
   // We need to draw this frame if we advanced to it while not skipping.
   if (advancement != kSkipFramesToCatchUp)
     GetImageObserver()->AnimationAdvanced(this);
 
   return true;
 }
 
 void BitmapImage::NotifyObserversOfAnimationAdvance(TimerBase*) {
-  GetImageObserver()->AnimationAdvanced(this);
+  if (GetImageObserver())
+    GetImageObserver()->AnimationAdvanced(this);
 }
 
 }  // namespace blink