When switching the visible uber frame, also switch focus.

chrome/browser/resources/uber/uber.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.
 
 cr.define('uber', function() {
   /**
    * Options for how web history should be handled.
    */
   var HISTORY_STATE_OPTION = {
     PUSH: 1,    // Push a new history state.
@@ skipping 349 matching lines @@
     // Trigger a layout after making it visible and before setting
     // the class to 'selected', so that it animates in.
     /** @suppress {uselessCode} */
     container.offsetTop;
     container.classList.add('selected');
 
     setContentChanging(true);
     adjustToScroll(0);
 
     var selectedFrame = getSelectedIframe().querySelector('iframe');
     uber.invokeMethodOnWindow(selectedFrame.contentWindow, 'frameSelected');

[Dan Beam, 2014/09/27 00:36:17]

if (!selectedFrame.contentDocument.hasFocus())

[Evan Stade, 2014/09/29 15:24:24]

what is the difference between having this check and not having this check?

[Dan Beam, 2014/09/29 19:15:47]

i believed this might break auto-focused fields (e.g. search in settings) and/or
double-focus a frame, but in trying it myself:
a) you can't access the contentDocument easily anyway (it seems)
b) re-focusing a window with focus doesn't dispatch another event

+    selectedFrame.contentWindow.focus();
 
     if (historyOption != HISTORY_STATE_OPTION.NONE)
       changePathTo({}, path, historyOption);
 
     if (container.dataset.title)
       document.title = container.dataset.title;
     assert('favicon' in container.dataset);
 
     var dataset = /** @type {{favicon: string}} */(container.dataset);
     $('favicon').href = 'chrome://theme/' + dataset.favicon;
@@ skipping 71 matching lines @@
   }
 
   return {
     onLoad: onLoad,
     onPopHistoryState: onPopHistoryState
   };
 });
 
 window.addEventListener('popstate', uber.onPopHistoryState);
 document.addEventListener('DOMContentLoaded', uber.onLoad);