Fix focus loss on chrome signin page

chrome/browser/resources/gaia_auth/main.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.
 
 /**
  * Authenticator class wraps the communications between Gaia and its host.
  */
 function Authenticator() {
 }
 
@@ skipping 213 matching lines @@
       'domain': extractDomain(msg.url)
     }, this.parentPage_);
   },
 
   onLoginUILoaded: function() {
     var msg = {
       'method': 'loginUILoaded'
     };
     window.parent.postMessage(msg, this.parentPage_);
     if (this.inlineMode_) {
-      $('gaia-frame').focus();
+      var gaiaFrame = $('gaia-frame');
+      gaiaFrame.focus();
+      gaiaFrame.onblur = function() {
+        gaiaFrame.focus();

[xiyuan, 2014/01/07 21:49:48]

Would this has side effect? e.g. what happens user click on omnibox or click
another browser window?

[guohui, 2014/01/07 22:15:02]

the only side effect i have observed is that upon switching back from another
window, the focused element may flicker once as it is refocused. I think it
should be ok as a temporary workaround until webview team fixes the root cause
on their side, TODO added.

+      };
     }
     this.loaded_ = true;
   },
 
   onConfirmLogin_: function() {
     if (!this.isSAMLFlow_) {
       this.completeLogin(this.email_, this.password_);
       return;
     }
 
@@ skipping 59 matching lines @@
     } else if (msg.method == 'redirectToSignin' &&
                this.isParentMessage_(e)) {
       $('gaia-frame').src = this.constructInitialFrameUrl_();
     } else {
        console.error('Authenticator.onMessage: unknown message + origin!?');
     }
   }
 };
 
 Authenticator.getInstance().initialize();