Oilpan: Completely move core/animations/ to oilpan's heap

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 966f73c12ead068bfb845eff5c9a09464cfb6f54..ad5ba4b68913f437c6a62129c13848a83b480260 100644
--- a/Source/core/animation/ActiveAnimations.h
+++ b/Source/core/animation/ActiveAnimations.h
@@ -63,21 +63,27 @@ public:
     CSSAnimations& cssAnimations() { return m_cssAnimations; }
     const CSSAnimations& cssAnimations() const { return m_cssAnimations; }
 
-    typedef HashMap<AnimationPlayer*, int> AnimationPlayerCountedSet;
+    typedef WillBeHeapHashMap<RawPtrWillBeWeakMember<AnimationPlayer>, int> AnimationPlayerCountedSet;
     // AnimationPlayers which have animations targeting this element.
     const AnimationPlayerCountedSet& players() const { return m_players; }
     void addPlayer(AnimationPlayer*);
     void removePlayer(AnimationPlayer*);
 
+#if ENABLE(OILPAN)
+    bool isEmpty() const { return m_defaultStack.isEmpty() && m_cssAnimations.isEmpty(); }
+#else
     bool isEmpty() const { return m_defaultStack.isEmpty() && m_cssAnimations.isEmpty() && m_animations.isEmpty(); }
+#endif
 
     void cancelAnimationOnCompositor();
 
     void updateAnimationFlags(RenderStyle&);
     void setAnimationStyleChange(bool animationStyleChange) { m_animationStyleChange = animationStyleChange; }
 
+#if !ENABLE(OILPAN)
     void addAnimation(Animation* animation) { m_animations.append(animation); }
     void notifyAnimationDestroyed(Animation* animation) { m_animations.remove(m_animations.find(animation)); }
+#endif
 
     void trace(Visitor*);
 
@@ -89,18 +95,10 @@ private:
     AnimationPlayerCountedSet m_players;
     bool m_animationStyleChange;
 
-    // This is to avoid a reference cycle that keeps Elements alive and
-    // won't be needed once Element and Animation are moved to Oilpan.
+#if !ENABLE(OILPAN)
+    // FIXME: Oilpan: This is to avoid a reference cycle that keeps Elements alive
+    // and won't be needed once the Node hierarchy becomes traceable.
     Vector<Animation*> m_animations;
-
-#if ENABLE(OILPAN)
-    // Keep a back reference to the target Element, so that this object
-    // will be finalized during the same GC sweep as the target (as the
-    // Element keeps a reference in the other direction via its
-    // rare data.) This is done so that we can accurately notify the
-    // the Element as destroyed to the above vector of Animations in
-    // the ActiveAnimations finalizer.
-    Member<Element> m_target;
 #endif
 
     // CSSAnimations checks if a style change is due to animation.