Implement animations for Independent CSS Transform Properties

Source/core/animation/DoubleStyleInterpolation.h

Index: Source/core/animation/DoubleStyleInterpolation.h
diff --git a/Source/core/animation/DoubleStyleInterpolation.h b/Source/core/animation/DoubleStyleInterpolation.h
index 7ac03f51b0297b51c982681a9296916d7048c2fa..e102b29445eaa63c8b775e98fa83ca45745fe51c 100644
--- a/Source/core/animation/DoubleStyleInterpolation.h
+++ b/Source/core/animation/DoubleStyleInterpolation.h
@@ -13,6 +13,8 @@ namespace blink {
 
 class CORE_EXPORT DoubleStyleInterpolation : public StyleInterpolation {
 public:
+    typedef void NonInterpolableType;
+
     static PassRefPtrWillBeRawPtr<DoubleStyleInterpolation> create(const CSSValue& start, const CSSValue& end, CSSPropertyID id, CSSPrimitiveValue::UnitType type, InterpolationRange clamp)
     {
         return adoptRefWillBeNoop(new DoubleStyleInterpolation(doubleToInterpolableValue(start), doubleToInterpolableValue(end), id, type == CSSPrimitiveValue::CSS_NUMBER, clamp, false));
@@ -26,6 +28,9 @@ public:
 
     DECLARE_VIRTUAL_TRACE();
 
+    static PassOwnPtrWillBeRawPtr<InterpolableValue> toInterpolableValue(const CSSValue&, CSSPropertyID = CSSPropertyInvalid);
+    static PassRefPtrWillBeRawPtr<CSSPrimitiveValue> fromInterpolableValue(const InterpolableValue&, InterpolationRange);
+
 private:
     DoubleStyleInterpolation(PassOwnPtrWillBeRawPtr<InterpolableValue> start, PassOwnPtrWillBeRawPtr<InterpolableValue> end, CSSPropertyID id, bool isNumber, InterpolationRange clamp, bool flag)
         : StyleInterpolation(start, end, id)