Use HeapHashCountedSet for AnimationPlayerCountedSet

Source/core/animation/ActiveAnimations.h

Index: Source/core/animation/ActiveAnimations.h
diff --git a/Source/core/animation/ActiveAnimations.h b/Source/core/animation/ActiveAnimations.h
index ba9b5b701234e1481de237a9e77206d15c8c2e8c..40bd6307e03e3fda285df6b8fff761481480e0a8 100644
--- a/Source/core/animation/ActiveAnimations.h
+++ b/Source/core/animation/ActiveAnimations.h
@@ -44,7 +44,7 @@ class CSSAnimations;
 class RenderObject;
 class Element;
 
-typedef WillBeHeapHashMap<RawPtrWillBeWeakMember<AnimationPlayer>, int> AnimationPlayerCountedSet;
+typedef WillBeHeapHashCountedSet<RawPtrWillBeWeakMember<AnimationPlayer> > AnimationPlayerCountedSet;
 
 class ActiveAnimations : public NoBaseWillBeGarbageCollectedFinalized<ActiveAnimations> {
     WTF_MAKE_NONCOPYABLE(ActiveAnimations);
@@ -67,9 +67,7 @@ public:
     const CSSAnimations& cssAnimations() const { return m_cssAnimations; }
 
     // AnimationPlayers which have animations targeting this element.
-    const AnimationPlayerCountedSet& players() const { return m_players; }
-    void addPlayer(AnimationPlayer*);
-    void removePlayer(AnimationPlayer*);
+    AnimationPlayerCountedSet& players() { return m_players; }
 
 #if ENABLE(OILPAN)
     bool isEmpty() const { return m_defaultStack.isEmpty() && m_cssAnimations.isEmpty(); }