Add additive animation support for CSS property clip

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

Index: third_party/WebKit/Source/core/animation/CSSClipInterpolationType.h
diff --git a/third_party/WebKit/Source/core/animation/CSSPathInterpolationType.h b/third_party/WebKit/Source/core/animation/CSSClipInterpolationType.h
similarity index 79%
copy from third_party/WebKit/Source/core/animation/CSSPathInterpolationType.h
copy to third_party/WebKit/Source/core/animation/CSSClipInterpolationType.h
index 647613960182eb5ec6942edc1f650dcccac201a9..45a3a6e134ef812294cb1edec9a60ecf0613ed1b 100644
--- a/third_party/WebKit/Source/core/animation/CSSPathInterpolationType.h
+++ b/third_party/WebKit/Source/core/animation/CSSClipInterpolationType.h
@@ -2,31 +2,33 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CSSPathInterpolationType_h
-#define CSSPathInterpolationType_h
+#ifndef CSSClipInterpolationType_h
+#define CSSClipInterpolationType_h
 
 #include "core/animation/CSSInterpolationType.h"
 
 namespace blink {
 
-class CSSPathInterpolationType : public CSSInterpolationType {
+class CSSClipInterpolationType : public CSSInterpolationType {
 public:
-    CSSPathInterpolationType(CSSPropertyID property)
+    CSSClipInterpolationType(CSSPropertyID property)
         : CSSInterpolationType(property)
-    { }
+    {
+        ASSERT(property == CSSPropertyClip);
+    }
 
-    void apply(const InterpolableValue&, const NonInterpolableValue*, InterpolationEnvironment&) const final;
+    InterpolationValue maybeConvertUnderlyingValue(const InterpolationEnvironment&) const final;
+    PairwiseInterpolationValue mergeSingleConversions(InterpolationValue& start, InterpolationValue& end) const final;
     void composite(UnderlyingValueOwner&, double underlyingFraction, const InterpolationValue&) const final;
+    void apply(const InterpolableValue&, const NonInterpolableValue*, InterpolationEnvironment&) const final;
 
-protected:
+private:
     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;
-    InterpolationValue maybeConvertUnderlyingValue(const InterpolationEnvironment&) const final;
-    PairwiseInterpolationValue mergeSingleConversions(InterpolationValue& start, InterpolationValue& end) const final;
 };
 
 } // namespace blink
 
-#endif // CSSPathInterpolationType_h
+#endif // CSSClipInterpolationType_h