[Oilpan] Migrate most classes under core/animations to Oilpan heap.

Source/core/animation/animatable/AnimatableLengthSize.h

Index: Source/core/animation/animatable/AnimatableLengthSize.h
diff --git a/Source/core/animation/animatable/AnimatableLengthSize.h b/Source/core/animation/animatable/AnimatableLengthSize.h
index 64aa8f71422afe8465d3786971b3d5c7e02d6112..cff812e7ce82bc200f993ee885786c48f716c61f 100644
--- a/Source/core/animation/animatable/AnimatableLengthSize.h
+++ b/Source/core/animation/animatable/AnimatableLengthSize.h
@@ -38,20 +38,20 @@ namespace blink {
 class AnimatableLengthSize final : public AnimatableValue {
 public:
     ~AnimatableLengthSize() override { }
-    static PassRefPtrWillBeRawPtr<AnimatableLengthSize> create(PassRefPtrWillBeRawPtr<AnimatableValue> width, PassRefPtrWillBeRawPtr<AnimatableValue> height)
+    static AnimatableLengthSize* create(AnimatableValue* width, AnimatableValue* height)
     {
-        return adoptRefWillBeNoop(new AnimatableLengthSize(width, height));
+        return new AnimatableLengthSize(width, height);
     }
-    const AnimatableValue* width() const { return m_width.get(); }
-    const AnimatableValue* height() const { return m_height.get(); }
+    const AnimatableValue* width() const { return m_width; }
+    const AnimatableValue* height() const { return m_height; }
 
     DECLARE_VIRTUAL_TRACE();
 
 protected:
-    PassRefPtrWillBeRawPtr<AnimatableValue> interpolateTo(const AnimatableValue*, double fraction) const override;
+    AnimatableValue* interpolateTo(const AnimatableValue*, double fraction) const override;
 
 private:
-    AnimatableLengthSize(PassRefPtrWillBeRawPtr<AnimatableValue> width, PassRefPtrWillBeRawPtr<AnimatableValue> height)
+    AnimatableLengthSize(AnimatableValue* width, AnimatableValue* height)
         : m_width(width)
         , m_height(height)
     {
@@ -59,8 +59,8 @@ private:
     AnimatableType type() const override { return TypeLengthSize; }
     bool equalTo(const AnimatableValue*) const override;
 
-    RefPtrWillBeMember<AnimatableValue> m_width;
-    RefPtrWillBeMember<AnimatableValue> m_height;
+    Member<AnimatableValue> m_width;
+    Member<AnimatableValue> m_height;
 };
 
 DEFINE_ANIMATABLE_VALUE_TYPE_CASTS(AnimatableLengthSize, isLengthSize());