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

Source/core/animation/LengthBoxStyleInterpolation.h

Index: Source/core/animation/LengthBoxStyleInterpolation.h
diff --git a/Source/core/animation/LengthBoxStyleInterpolation.h b/Source/core/animation/LengthBoxStyleInterpolation.h
index 748dfc793ab32170870abdee331e2d2cf9a128b3..2f91f64a27bffc0e3bf16215da5c9ae71c34dd3d 100644
--- a/Source/core/animation/LengthBoxStyleInterpolation.h
+++ b/Source/core/animation/LengthBoxStyleInterpolation.h
@@ -14,7 +14,7 @@ namespace blink {
 
 class CORE_EXPORT LengthBoxStyleInterpolation : public StyleInterpolation {
 public:
-    static PassRefPtrWillBeRawPtr<LengthBoxStyleInterpolation> maybeCreateFrom(CSSValue&, CSSValue&, CSSPropertyID);
+    static LengthBoxStyleInterpolation* maybeCreateFrom(CSSValue&, CSSValue&, CSSPropertyID);
 
     static bool usesDefaultInterpolation(const CSSValue&, const CSSValue&);
 
@@ -22,13 +22,13 @@ public:
     DECLARE_VIRTUAL_TRACE();
 
 private:
-    LengthBoxStyleInterpolation(PassOwnPtrWillBeRawPtr<InterpolableValue> startInterpolation, PassOwnPtrWillBeRawPtr<InterpolableValue> endInterpolation, CSSPropertyID id, CSSValue* startCSS, CSSValue* endCSS)
+    LengthBoxStyleInterpolation(InterpolableValue* startInterpolation, InterpolableValue* endInterpolation, CSSPropertyID id, CSSValue* startCSS, CSSValue* endCSS)
         : StyleInterpolation(startInterpolation, endInterpolation, id)
         , m_startCSSValue(startCSS)
         , m_endCSSValue(endCSS)
     { }
 
-    static PassOwnPtrWillBeRawPtr<InterpolableValue> lengthBoxtoInterpolableValue(const CSSValue&, const CSSValue&, bool);
+    static InterpolableValue* lengthBoxtoInterpolableValue(const CSSValue&, const CSSValue&, bool);
     static PassRefPtrWillBeRawPtr<CSSValue> interpolableValueToLengthBox(InterpolableValue*, const CSSValue&, const CSSValue&);
 
     RefPtrWillBeMember<CSSValue> m_startCSSValue;