reland -- Disable animations during aura tests.

ui/gfx/compositor/layer_animation_observer.h

Index: ui/gfx/compositor/layer_animation_observer.h
diff --git a/ui/gfx/compositor/layer_animation_observer.h b/ui/gfx/compositor/layer_animation_observer.h
index c35dc60cbae411a1cd1917d7647d295dba4ceb26..50b697b4e86af02a01f462841936432b0fb334d4 100644
--- a/ui/gfx/compositor/layer_animation_observer.h
+++ b/ui/gfx/compositor/layer_animation_observer.h
@@ -16,6 +16,7 @@ namespace ui {
 
 class LayerAnimationSequence;
 class ScopedLayerAnimationSettings;
+class ImplicitAnimationObserver;
 
 // LayerAnimationObservers are notified when animations complete.
 class COMPOSITOR_EXPORT LayerAnimationObserver  {
@@ -40,6 +41,8 @@ class COMPOSITOR_EXPORT LayerAnimationObserver  {
   // OBSERVER WHEN YOU ARE DESTROYED.
   virtual bool RequiresNotificationWhenAnimatorDestroyed() const;
 
+  virtual ImplicitAnimationObserver* AsImplicitObserver() { return NULL; }
+
  protected:
   LayerAnimationObserver();
   virtual ~LayerAnimationObserver();
@@ -81,6 +84,7 @@ class COMPOSITOR_EXPORT ImplicitAnimationObserver
       const LayerAnimationSequence* sequence) OVERRIDE;
   virtual void OnLayerAnimationScheduled(
       const LayerAnimationSequence* sequence) OVERRIDE;
+  virtual ImplicitAnimationObserver* AsImplicitObserver() { return this; }
 
   void CheckCompleted();