Use alias_for with trivial property aliases

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/AngleSVGInterpolation.h"
 #include "core/animation/ColorStyleInterpolation.h"
 #include "core/animation/CompositorAnimations.h"
@@ skipping 315 matching lines @@
         if (interpolation)
             return interpolation.release();
 
         // FIXME: Handle keywords: top, right, left, center, bottom
         fallBackToLegacy = true;
 
         break;
     }
 
     case CSSPropertyBoxShadow:
-    case CSSPropertyTextShadow:
-    case CSSPropertyWebkitBoxShadow: {
+    case CSSPropertyTextShadow: {
         RefPtrWillBeRawPtr<Interpolation> interpolation = ListStyleInterpolation<ShadowStyleInterpolation>::maybeCreateFromList(*fromCSSValue, *toCSSValue, property);
         if (interpolation)
             return interpolation.release();
 
         // FIXME: AnimatableShadow incorrectly animates between inset and non-inset values so it will never indicate it needs default interpolation
         if (ShadowStyleInterpolation::usesDefaultStyleInterpolation(*fromCSSValue, *toCSSValue)) {
             forceDefaultInterpolation = true;
             break;
         }
 
@@ skipping 148 matching lines @@
     RefPtrWillBeRawPtr<SVGPropertyBase> fromValue = attribute->currentValueBase()->cloneForAnimation(m_value);
     RefPtrWillBeRawPtr<SVGPropertyBase> toValue = attribute->currentValueBase()->cloneForAnimation(toSVGPropertySpecificKeyframe(end).value());
 
     if (!fromValue || !toValue)
         return nullptr;
 
     return createSVGInterpolation(fromValue.get(), toValue.get(), attribute.get());
 }
 
 }