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

Source/core/animation/animatable/AnimatableDoubleAndBool.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/animation/animatable/AnimatableDoubleAndBool.h"
 
 #include "platform/animation/AnimationUtilities.h"
 
 namespace blink {
 
 bool AnimatableDoubleAndBool::usesDefaultInterpolationWith(const AnimatableValue* value) const
 {
     const AnimatableDoubleAndBool* other = toAnimatableDoubleAndBool(value);
     return flag() != other->flag();
 }
 
-PassRefPtrWillBeRawPtr<AnimatableValue> AnimatableDoubleAndBool::interpolateTo(const AnimatableValue* value, double fraction) const
+AnimatableValue* AnimatableDoubleAndBool::interpolateTo(const AnimatableValue* value, double fraction) const
 {
     const AnimatableDoubleAndBool* other = toAnimatableDoubleAndBool(value);
     if (flag() == other->flag())
         return AnimatableDoubleAndBool::create(blend(m_number, other->m_number, fraction), flag());
 
     return defaultInterpolateTo(this, value, fraction);
 }
 
 bool AnimatableDoubleAndBool::equalTo(const AnimatableValue* value) const
 {
     const AnimatableDoubleAndBool* other = toAnimatableDoubleAndBool(value);
     return toDouble() == other->toDouble() && flag() == other->flag();
 }
 
 }