Animation: Implement DoubleStyleInterpolation in StringKeyframe

Source/core/animation/StyleInterpolation.h

 // 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.
 
 #ifndef StyleInterpolation_h
 #define StyleInterpolation_h
 
 #include "core/CSSPropertyNames.h"
 #include "core/animation/Interpolation.h"
 
 namespace blink {
 
 class StyleResolverState;
 
 enum InterpolationRange {
     RangeNonNegative,
-    RangeOpacityFIXME,
+    RangeFloatFractions,
+    RangeFloor,
+    RangeDoubleFractions,
+    RangeCeiling,
+    RangeGreaterThanOne,
     RangeAll
 };
 
 class StyleInterpolation : public Interpolation {
 public:
     // 1) convert m_cachedValue into an X
     // 2) shove X into StyleResolverState
     // X can be:
     // (1) a CSSValue (and applied via StyleBuilder::applyProperty)
     // (2) an AnimatableValue (and applied via // AnimatedStyleBuilder::applyProperty)
@@ skipping 17 matching lines @@
         , m_id(id)
     {
     }
 };
 
 DEFINE_TYPE_CASTS(StyleInterpolation, Interpolation, value, value->isStyleInterpolation(), value.isStyleInterpolation());
 
 }
 
 #endif