Fix SHIFT+TAB order on GAIA login screens

chrome/browser/resources/gaia_auth_host/authenticator.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.
 
 <include src="saml_handler.js">
 
 /**
  * @fileoverview An UI component to authenciate to Chrome. The component hosts
  * IdP web pages in a webview. A client who is interested in monitoring
  * authentication events should pass a listener object of type
@@ skipping 304 matching lines @@
     else
       history.replaceState({url: url}, '');
   };
 
   /**
    * Invoked when the sign-in page takes focus.
    * @param {object} e The focus event being triggered.
    * @private
    */
   Authenticator.prototype.onFocus_ = function(e) {
-    this.webview_.focus();
+    if (!this.isNewGaiaFlowChromeOS)

[xiyuan, 2015/06/10 17:43:03]

It is probably more correct to check (authMode == AuthMode.DESKTOP). 
How about remember authMode in Authenticator.prototype.load and test it here?

The worry is that we might switch to new gaia flow in ChromeOS mirror later and
would run it in a tab as well. And isNewGaiaFlowChromeOS might not tell the
difference.

[Greg Levin, 2015/06/10 20:01:25]

Done.

+      this.webview_.focus();
   };
 
   /**
    * Invoked when the history state is changed.
    * @param {object} e The popstate event being triggered.
    * @private
    */
   Authenticator.prototype.onPopState_ = function(e) {
     var state = e.state;
     if (state && state.url)
@@ skipping 349 matching lines @@
   Authenticator.AuthMode = AuthMode;
   Authenticator.SUPPORTED_PARAMS = SUPPORTED_PARAMS;
 
   return {
     // TODO(guohui, xiyuan): Rename GaiaAuthHost to Authenticator once the old
     // iframe-based flow is deprecated.
     GaiaAuthHost: Authenticator,
     Authenticator: Authenticator
   };
 });