Show MessageWindow from the background page

remoting/webapp/js_proto/chrome_proto.js

Index: remoting/webapp/js_proto/chrome_proto.js
diff --git a/remoting/webapp/js_proto/chrome_proto.js b/remoting/webapp/js_proto/chrome_proto.js
index ba9d3bbc7ac5962e8950971f8a5ac11c2b29925c..dfa7f9f6221f05334c4da7c408482b5d4c64cb0f 100644
--- a/remoting/webapp/js_proto/chrome_proto.js
+++ b/remoting/webapp/js_proto/chrome_proto.js
@@ -332,6 +332,8 @@ var AppWindow = function() {
   /** @type {Window} */
   this.contentWindow = null;
   /** @type {chrome.Event} */
+  this.onClosed = null;
+  /** @type {chrome.Event} */
   this.onRestored = null;
   /** @type {chrome.Event} */
   this.onMaximized = null;
@@ -346,6 +348,7 @@ AppWindow.prototype.drawAttention = function() {};
 AppWindow.prototype.maximize = function() {};
 AppWindow.prototype.minimize = function() {};
 AppWindow.prototype.restore = function() {};
+AppWindow.prototype.show = function() {};
 AppWindow.prototype.fullscreen = function() {};
 /** @return {boolean} */
 AppWindow.prototype.isFullscreen = function() {};