Oilpan: Move AnimatableValue's hierarchy to oilpan's heap

Source/core/animation/AnimatableVisibility.h

Index: Source/core/animation/AnimatableVisibility.h
diff --git a/Source/core/animation/AnimatableVisibility.h b/Source/core/animation/AnimatableVisibility.h
index c0c7433554552b0a9a8f8477dcc63626721755c8..2b344b33b41ece0ec7ad65d7d7f09e90d3b6d36a 100644
--- a/Source/core/animation/AnimatableVisibility.h
+++ b/Source/core/animation/AnimatableVisibility.h
@@ -39,15 +39,17 @@ namespace WebCore {
 class AnimatableVisibility FINAL : public AnimatableValue {
 public:
     virtual ~AnimatableVisibility() { }
-    static PassRefPtr<AnimatableVisibility> create(EVisibility visibility)
+    static PassRefPtrWillBeRawPtr<AnimatableVisibility> create(EVisibility visibility)
     {
-        return adoptRef(new AnimatableVisibility(visibility));
+        return adoptRefWillBeNoop(new AnimatableVisibility(visibility));
     }
 
     EVisibility visibility() const { return m_visibility; }
 
+    virtual void trace(Visitor*) OVERRIDE { }
+
 protected:
-    virtual PassRefPtr<AnimatableValue> interpolateTo(const AnimatableValue*, double fraction) const OVERRIDE;
+    virtual PassRefPtrWillBeRawPtr<AnimatableValue> interpolateTo(const AnimatableValue*, double fraction) const OVERRIDE;
     virtual bool usesDefaultInterpolationWith(const AnimatableValue*) const OVERRIDE;
 
 private: