Geometry: Reimplement DOMPoint using V8 extras.

third_party/WebKit/Source/modules/geometry/DOMPoint.js

+// Copyright 2016 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.
+
+(function(global, binding, v8) {
+  'use strict';
+
+  const defineProperty = global.Object.defineProperty;
+
+  const {
+    domPointX: _x,
+    domPointY: _y,
+    domPointZ: _z,
+    domPointW: _w,
+    ensureDOMPoint: ensureDOMPoint
+  } = binding;
+
+  class DOMPoint extends DOMPointReadOnly {
+    constructor(x = 0, y = 0, z = 0, w = 1) {
+      super(x, y, z, w);
+    }
+
+    get x() {
+      ensureDOMPoint(this);
+      return this[_x];
+    }
+
+    set x(x) {
+      ensureDOMPoint(this);
+      this[_x] = +x;
+    }
+
+    get y() {
+      ensureDOMPoint(this);
+      return this[_y];
+    }
+
+    set y(y) {
+      ensureDOMPoint(this);
+      this[_y] = +y;
+    }
+
+    get z() {
+      ensureDOMPoint(this);
+      return this[_z];
+    }
+
+    set z(z) {
+      ensureDOMPoint(this);
+      this[_z] = +z;
+    }
+
+    get w() {
+      ensureDOMPoint(this);
+      return this[_w];
+    }
+
+    set w(w) {
+      ensureDOMPoint(this);
+      this[_w] = +w;
+    }
+
+    static fromPoint(init) {
+      return new DOMPoint(init.x, init.y, init.z, init.w);
+    }
+  }
+
+  binding.createDOMPoint = (x, y, z, w) => new DOMPoint(x, y, z, w);
+  binding.updateDOMPoint = function(obj, x, y, z, w) {
+    if (_x in obj) {
+      obj[_x] = +x;
+      obj[_y] = +y;
+      obj[_z] = +z;
+      obj[_w] = +w;
+    }
+  };
+
+  defineProperty(global, 'DOMPoint', {
+    value: DOMPoint,
+    configurable: true,
+    enumerable: false,
+    writable: true
+  });
+});