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

Source/core/animation/animatable/AnimatableImage.cpp

 /*
  * 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 29 matching lines @@
 // FIXME: Once cross-fade works on generated image types, remove this method.
 bool AnimatableImage::usesDefaultInterpolationWith(const AnimatableValue* value) const
 {
     if (!m_value->isImageValue())
         return true;
     if (!toAnimatableImage(value)->toCSSValue()->isImageValue())
         return true;
     return false;
 }
 
-PassRefPtrWillBeRawPtr<AnimatableValue> AnimatableImage::interpolateTo(const AnimatableValue* value, double fraction) const
+AnimatableValue* AnimatableImage::interpolateTo(const AnimatableValue* value, double fraction) const
 {
     if (fraction <= 0 || fraction >= 1 || usesDefaultInterpolationWith(value))
         return defaultInterpolateTo(this, value, fraction);
 
     CSSValue* fromValue = toCSSValue();
     CSSValue* toValue = toAnimatableImage(value)->toCSSValue();
 
     RefPtrWillBeRawPtr<CSSCrossfadeValue> crossfadeValue = CSSCrossfadeValue::create(fromValue, toValue);
     crossfadeValue->setPercentage(CSSPrimitiveValue::create(fraction, CSSPrimitiveValue::CSS_NUMBER));
     return create(crossfadeValue);
 }
 
 bool AnimatableImage::equalTo(const AnimatableValue* value) const
 {
     return m_value->equals(*toAnimatableImage(value)->m_value.get());
 }
 
 }