Add null checks of GetImageObserver() in BitmapImage

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

Index: third_party/WebKit/Source/platform/graphics/BitmapImage.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/BitmapImage.cpp b/third_party/WebKit/Source/platform/graphics/BitmapImage.cpp
index de68c82b52646e7fee938fad1a848c70ef5cf684..7e6ca635ef63af01b6d6daaa8e4590e6a95d6b37 100644
--- a/third_party/WebKit/Source/platform/graphics/BitmapImage.cpp
+++ b/third_party/WebKit/Source/platform/graphics/BitmapImage.cpp
@@ -604,6 +604,9 @@ 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.
@@ -654,7 +657,8 @@ bool BitmapImage::InternalAdvanceAnimation(AnimationAdvancement advancement) {
 }
 
 void BitmapImage::NotifyObserversOfAnimationAdvance(TimerBase*) {
-  GetImageObserver()->AnimationAdvanced(this);
+  if (GetImageObserver())
+    GetImageObserver()->AnimationAdvanced(this);
 }
 
 }  // namespace blink