extensions: fix focus management for all dialogs (not just options).

ui/webui/resources/js/cr/ui/page_manager/page.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="../node_utils.js">
 
 cr.define('cr.ui.pageManager', function() {
   var PageManager = cr.ui.pageManager.PageManager;
 
   /**
@@ skipping 61 matching lines @@
      * Called by the PageManager when this.hash changes while the page is
      * already visible. This is analogous to the hashchange DOM event.
      */
     didChangeHash: function() {},
 
     /**
      * Sets focus on the first focusable element. Override for a custom focus
      * strategy.
      */
     focus: function() {
-      // Do not change focus if any control on this page is already focused.
-      if (this.pageDiv.contains(document.activeElement))
-        return;
-
-      var elements = this.pageDiv.querySelectorAll(
-          'input, list, select, textarea, button');
-      for (var i = 0; i < elements.length; i++) {
-        var element = elements[i];
-        // Try to focus. If fails, then continue.
-        element.focus();
-        if (document.activeElement == element)
-          return;
-      }
+      cr.ui.setInitialFocus(this.pageDiv);
     },
 
     /**
      * Reverse any buttons strips in this page (only applies to overlays).
      * @see cr.ui.reverseButtonStrips for an explanation of why this is
      * necessary and when it's done.
      */
     reverseButtonStrip: function() {
       assert(this.isOverlay);
       cr.ui.reverseButtonStrips(this.pageDiv);
@@ skipping 205 matching lines @@
         PageManager.onPageVisibilityChanged(this);
       }
     },
   };
 
   // Export
   return {
     Page: Page
   };
 });