Add additive animation support for CSS property translate

third_party/WebKit/Source/core/animation/CSSTranslateInterpolationType.h

-// Copyright 2015 The Chromium Authors. All rights reserved.
+// Copyright 2016 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.
 
-#ifndef CSSNumberInterpolationType_h
-#define CSSNumberInterpolationType_h
+#ifndef CSSTranslateInterpolationType_h
+#define CSSTranslateInterpolationType_h
 
 #include "core/animation/CSSInterpolationType.h"
 
 namespace blink {
 
-class CSSNumberInterpolationType : public CSSInterpolationType {
+class CSSTranslateInterpolationType : public CSSInterpolationType {
 public:
-    CSSNumberInterpolationType(CSSPropertyID property)
+    CSSTranslateInterpolationType(CSSPropertyID property)
         : CSSInterpolationType(property)
-    { }
+    {
+        ASSERT(property == CSSPropertyTranslate);
+    }
 
     InterpolationValue maybeConvertUnderlyingValue(const InterpolationEnvironment&) const final;
     void apply(const InterpolableValue&, const NonInterpolableValue*, InterpolationEnvironment&) const final;
 
 private:
-    InterpolationValue createNumberValue(double number) const;
     InterpolationValue maybeConvertNeutral(const InterpolationValue& underlying, ConversionCheckers&) const final;
     InterpolationValue maybeConvertInitial() const final;
     InterpolationValue maybeConvertInherit(const StyleResolverState&, ConversionCheckers&) const final;
     InterpolationValue maybeConvertValue(const CSSValue&, const StyleResolverState&, ConversionCheckers&) const final;
+
 };
 
 } // namespace blink
 
-#endif // CSSNumberInterpolationType_h
+#endif // CSSTranslateInterpolationType_h