Use alias_for with trivial property aliases

Source/core/animation/css/CSSAnimations.cpp

Index: Source/core/animation/css/CSSAnimations.cpp
diff --git a/Source/core/animation/css/CSSAnimations.cpp b/Source/core/animation/css/CSSAnimations.cpp
index 284a1f9b87a25340b325f706736153f5a531befc..e83ea7eb8c60993a1417fe6c7d7b0945204c4847 100644
--- a/Source/core/animation/css/CSSAnimations.cpp
+++ b/Source/core/animation/css/CSSAnimations.cpp
@@ -71,16 +71,10 @@ CSSPropertyID propertyForAnimation(CSSPropertyID property)
     switch (property) {
     case CSSPropertyWebkitBackgroundSize:
         return CSSPropertyBackgroundSize;
-    case CSSPropertyWebkitBoxShadow:
-        return CSSPropertyBoxShadow;
     case CSSPropertyWebkitPerspective:
         return CSSPropertyPerspective;
     case CSSPropertyWebkitTransform:
         return CSSPropertyTransform;
-    case CSSPropertyWebkitPerspectiveOrigin:
-        return CSSPropertyPerspectiveOrigin;
-    case CSSPropertyWebkitTransformOrigin:
-        return CSSPropertyTransformOrigin;
     default:
         break;
     }