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

Source/core/animation/animatable/AnimatableNeutral.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 24 matching lines @@
 
 namespace blink {
 
 class AnimatableNeutral final : public AnimatableValue {
 public:
     ~AnimatableNeutral() override { }
 
     DEFINE_INLINE_VIRTUAL_TRACE() { AnimatableValue::trace(visitor); }
 
 protected:
-    static PassRefPtrWillBeRawPtr<AnimatableNeutral> create() { return adoptRefWillBeNoop(new AnimatableNeutral()); }
-    PassRefPtrWillBeRawPtr<AnimatableValue> interpolateTo(const AnimatableValue* value, double fraction) const override
+    static AnimatableNeutral* create() { return new AnimatableNeutral; }
+    AnimatableValue* interpolateTo(const AnimatableValue* value, double fraction) const override
     {
         ASSERT_NOT_REACHED();
         return nullptr;
     }
 
 private:
     friend class AnimatableValue;
     AnimatableType type() const override { return TypeNeutral; }
     bool equalTo(const AnimatableValue* value) const override
     {
         ASSERT_NOT_REACHED();
         return true;
     }
 };
 
 } // namespace blink
 
 #endif // AnimatableNeutral_h