Store [-webkit-]perspective-origin as a LengthPoint.

Source/core/css/resolver/AnimatedStyleBuilder.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 542 matching lines @@
         return;
     case CSSPropertyWebkitMaskPositionY:
         setOnFillLayers<CSSPropertyWebkitMaskPositionY>(style->accessMaskLayers(), value, state);
         return;
     case CSSPropertyWebkitMaskSize:
         setOnFillLayers<CSSPropertyWebkitMaskSize>(style->accessMaskLayers(), value, state);
         return;
     case CSSPropertyPerspective:
         style->setPerspective(clampTo<float>(toAnimatableDouble(value)->toDouble()));
         return;
-    case CSSPropertyPerspectiveOrigin: {
-        const AnimatableLengthPoint* animatableLengthPoint = toAnimatableLengthPoint(value);
-        style->setPerspectiveOriginX(animatableValueToLength(animatableLengthPoint->x(), state));
-        style->setPerspectiveOriginY(animatableValueToLength(animatableLengthPoint->y(), state));
+    case CSSPropertyPerspectiveOrigin:
+        style->setPerspectiveOrigin(animatableValueToLengthPoint(value, state));
         return;
-    }
     case CSSPropertyShapeOutside:
         style->setShapeOutside(toAnimatableShapeValue(value)->shapeValue());
         return;
     case CSSPropertyShapeMargin:
         style->setShapeMargin(animatableValueToLength(value, state, ValueRangeNonNegative));
         return;
     case CSSPropertyShapeImageThreshold:
         style->setShapeImageThreshold(clampTo<float>(toAnimatableDouble(value)->toDouble(), 0, 1));
         return;
     case CSSPropertyWebkitTextStrokeColor:
@@ skipping 33 matching lines @@
         return;
     case CSSPropertyZoom:
         style->setZoom(clampTo<float>(toAnimatableDouble(value)->toDouble(), std::numeric_limits<float>::denorm_min()));
         return;
     default:
         ASSERT_NOT_REACHED();
     }
 }
 
 } // namespace blink