UI Compositor Animation: Remove cc::ElementAnimations state storage.

cc/animation/animation_host.h

Index: cc/animation/animation_host.h
diff --git a/cc/animation/animation_host.h b/cc/animation/animation_host.h
index 1a877d96830d8b3982570effa96df9c0eb4d4ce2..a81df79f094e1501984d6be5cd313f1612f9ddba 100644
--- a/cc/animation/animation_host.h
+++ b/cc/animation/animation_host.h
@@ -165,11 +165,6 @@ class CC_EXPORT AnimationHost {
   // element animations will no longer be ticked (since it's not active).
   void DidDeactivateElementAnimations(ElementAnimations* element_animations);
 
-  // Registers the given ElementAnimations as alive.
-  void RegisterElementAnimations(ElementAnimations* element_animations);
-  // Unregisters the given ElementAnimations as alive.
-  void UnregisterElementAnimations(ElementAnimations* element_animations);
-
   const ElementToAnimationsMap& active_element_animations_for_testing() const;
   const ElementToAnimationsMap& all_element_animations_for_testing() const;