[GeometryInterface] add transformPoint(point) function.

third_party/WebKit/Source/core/dom/DOMMatrixReadOnly.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.
 
 // http://dev.w3.org/fxtf/geometry/#DOMMatrix
 
 [
     Constructor(sequence<unrestricted double> numberSequence),
     RaisesException=Constructor,
     // FIXME: Exposed=(Window,Worker)
@@ skipping 54 matching lines @@
                               optional unrestricted double y = 0,
                               optional unrestricted double z = 0,
                               optional unrestricted double angle = 0);
     DOMMatrix skewX(optional unrestricted double sx = 0);
     DOMMatrix skewY(optional unrestricted double sy = 0);
     [RaisesException] DOMMatrix multiply(optional DOMMatrixInit other);
     DOMMatrix flipX();
     DOMMatrix flipY();
     DOMMatrix inverse();
 
+    DOMPoint transformPoint(optional DOMPointInit point);
+
     Float32Array toFloat32Array();
     Float64Array toFloat64Array();
     stringifier;
 };