Adding fromPoint to DOMPoint and DOMPointReadOnly interfaces following spec.

third_party/WebKit/Source/core/dom/DOMPoint.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 "core/dom/DOMPoint.h"
 
 #include "core/dom/DOMPointInit.h"
 
 namespace blink {
 
 DOMPoint* DOMPoint::create(const DOMPointInit& point) {
   return new DOMPoint(point.x(), point.y(), point.z(), point.w());
 }
 
 DOMPoint* DOMPoint::create(double x, double y, double z, double w) {
   return new DOMPoint(x, y, z, w);
 }
 
+DOMPoint* DOMPoint::fromPoint(const DOMPointInit& other) {
+  return new DOMPoint(other.x(), other.y(), other.z(), other.w());
+}
+
 DOMPoint::DOMPoint(double x, double y, double z, double w)
     : DOMPointReadOnly(x, y, z, w) {}
 
 }  // namespace blink