Store [-webkit-]transform-origin as a TransformOrigin.

Source/core/css/resolver/StyleBuilderConverter.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  *     * 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
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 762 matching lines @@
 float StyleBuilderConverter::convertTextStrokeWidth(StyleResolverState& state, CSSValue* value)
 {
     CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);
     if (primitiveValue->getValueID()) {
         float multiplier = convertLineWidth<float>(state, value);
         return CSSPrimitiveValue::create(multiplier / 48, CSSPrimitiveValue::CSS_EMS)->computeLength<float>(state.cssToLengthConversionData());
     }
     return primitiveValue->computeLength<float>(state.cssToLengthConversionData());
 }
 
+TransformOrigin StyleBuilderConverter::convertTransformOrigin(StyleResolverState& state, CSSValue* value)
+{
+    CSSValueList* list = toCSSValueList(value);
+    ASSERT(list->length() == 3);
+
+    CSSPrimitiveValue* primitiveValueX = toCSSPrimitiveValue(list->item(0));
+    CSSPrimitiveValue* primitiveValueY = toCSSPrimitiveValue(list->item(1));
+    CSSPrimitiveValue* primitiveValueZ = toCSSPrimitiveValue(list->item(2));
+
+    return TransformOrigin(
+        convertOriginLength<CSSValueLeft, CSSValueRight>(state, primitiveValueX),
+        convertOriginLength<CSSValueTop, CSSValueBottom>(state, primitiveValueY),
+        StyleBuilderConverter::convertComputedLength<float>(state, primitiveValueZ)
+    );
+}
+
 } // namespace blink