Adding fromPoint to DOMPoint and DOMPointReadOnly interfaces following spec.

third_party/WebKit/Source/core/dom/DOMPoint.idl

 // 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.
 
 // https://dev.w3.org/fxtf/geometry/#DOMPoint
 
 [
     // FIXME: The point argument is optional in the spec:
     // https://www.w3.org/Bugs/Public/show_bug.cgi?id=28108
     Constructor(DOMPointInit point),
     Constructor(optional unrestricted double x = 0, optional unrestricted double y = 0,
                 optional unrestricted double z = 0, optional unrestricted double w = 1),
     // FIXME: Exposed=(Window,Worker)
     RuntimeEnabled=GeometryInterfaces,
 ] interface DOMPoint : DOMPointReadOnly {
+    [NewObject] static DOMPoint fromPoint(optional DOMPointInit other);
     inherit attribute unrestricted double x;
     inherit attribute unrestricted double y;
     inherit attribute unrestricted double z;
     inherit attribute unrestricted double w;
 };