remoting.WindowShape clean up.

remoting/webapp/app_remoting/js/context_menu_dom.js

 // 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.
 
 /**
  * @fileoverview
  * Provide an alternative location for the application's context menu items
  * on platforms that don't provide it.
  *
  * To mimic the behaviour of an OS-provided context menu, the menu is dismissed
@@ skipping 56 matching lines @@
 
   this.eventSource_.defineEvents([this.eventName_]);
   this.root_.addEventListener(
       'transitionend', this.onTransitionEnd_.bind(this), false);
   this.stub_.addEventListener('click', this.onStubClick_.bind(this), false);
   this.icon_.addEventListener('click', this.onIconClick_.bind(this), false);
   this.screen_.addEventListener('click', this.onIconClick_.bind(this), false);
 
   this.root_.hidden = false;
   this.root_.style.bottom = this.bottom_ + 'px';
-  remoting.windowShape.addCallback(this);
+  remoting.windowShape.registerClientUI(this);
+};
+
+remoting.ContextMenuDom.prototype.dispose = function() {
+  remoting.windowShape.unregisterClientUI(this);
 };
 
 /**
  * @param {Array<{left: number, top: number, width: number, height: number}>}
  *     rects List of rectangles.
  */
 remoting.ContextMenuDom.prototype.addToRegion = function(rects) {
   var rect = /** @type {ClientRect} */ (this.root_.getBoundingClientRect());
   // Clip the menu position to the main window in case the screen size has
   // changed or a recent drag event tried to move it out of bounds.
@@ skipping 206 matching lines @@
   this.bottom_ -= deltaY;
   this.root_.style.bottom = this.bottom_ + 'px';
   // Deferring the window shape update until the DOM update has completed
   // helps keep the position of the context menu consistent with the window
   // shape (though it's still not perfect).
   window.requestAnimationFrame(
       function() {
         remoting.windowShape.updateClientWindowShape();
       });
 };