Animation: FilterStyleInterpolation for animating filter

Source/core/animation/StringKeyframe.cpp

 // Copyright 2014 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.
 
 #include "config.h"
 #include "core/animation/StringKeyframe.h"
 
 #include "core/animation/ColorStyleInterpolation.h"
 #include "core/animation/CompositorAnimations.h"
 #include "core/animation/ConstantStyleInterpolation.h"
 #include "core/animation/DeferredLegacyStyleInterpolation.h"
 #include "core/animation/DoubleStyleInterpolation.h"
+#include "core/animation/FilterStyleInterpolation.h"
 #include "core/animation/ImageSliceStyleInterpolation.h"
 #include "core/animation/ImageStyleInterpolation.h"
 #include "core/animation/LegacyStyleInterpolation.h"
 #include "core/animation/LengthBoxStyleInterpolation.h"
 #include "core/animation/LengthPairStyleInterpolation.h"
 #include "core/animation/LengthStyleInterpolation.h"
 #include "core/animation/ListStyleInterpolation.h"
 #include "core/animation/SVGStrokeDasharrayStyleInterpolation.h"
 #include "core/animation/ShadowStyleInterpolation.h"
 #include "core/animation/VisibilityStyleInterpolation.h"
@@ skipping 326 matching lines @@
     }
 
     case CSSPropertyStrokeDasharray: {
         RefPtrWillBeRawPtr<Interpolation> interpolation = SVGStrokeDasharrayStyleInterpolation::maybeCreate(*fromCSSValue, *toCSSValue, property);
         if (interpolation)
             return interpolation.release();
 
         break;
     }
 
+    case CSSPropertyWebkitFilter: {
+        RefPtrWillBeRawPtr<Interpolation> interpolation = FilterStyleInterpolation::maybeCreate(*fromCSSValue, *toCSSValue, property);
+        if (interpolation)
+            return interpolation.release();
+
+        // FIXME: Support drop shadow interpolation.
+        fallBackToLegacy = true;
+        break;
+    }
+
     default:
         // Fall back to LegacyStyleInterpolation.
         fallBackToLegacy = true;
         break;
     }
 
     if (fromCSSValue == toCSSValue)
         return ConstantStyleInterpolation::create(fromCSSValue, property);
 
     if (forceDefaultInterpolation)
@@ skipping 37 matching lines @@
 }
 
 DEFINE_TRACE(StringKeyframe::PropertySpecificKeyframe)
 {
     visitor->trace(m_value);
     visitor->trace(m_animatableValueCache);
     Keyframe::PropertySpecificKeyframe::trace(visitor);
 }
 
 }