Implement apps v2 custom window frame.

remoting/webapp/background.js

 // Copyright (c) 2012 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.
 
 /** @type {string} */
 var kNewWindowId = 'new-window';
 
 function createWindow() {
   chrome.app.window.create('main.html', {
     'width': 800,
-    'height': 600
+    'height': 600,
+    'frame': 'none'
   });
 };
 
 /** @param {OnClickData} info */
 function onContextMenu(info) {
   if (info.menuItemId == kNewWindowId) {
     createWindow();
   }
 };
 
 function initializeContextMenu() {
   chrome.contextMenus.create({
      id: kNewWindowId,
      contexts: ['launcher'],
      title: chrome.i18n.getMessage(/*i18n-content*/'NEW_WINDOW')
   });
 }
 
 chrome.app.runtime.onLaunched.addListener(createWindow);
 chrome.contextMenus.onClicked.addListener(onContextMenu);
 initializeContextMenu();