Added aria-hidden attribute to elements obscured behind an overlay to aid screen readers.

chrome/browser/resources/options2/options_page.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('options', function() {
   /////////////////////////////////////////////////////////////////////////////
   // OptionsPage class:
 
   /**
    * Base class for options page.
@@ skipping 233 matching lines @@
       this.showPageByName(overlay.parentPage.name, false);
 
     if (!overlay.visible) {
       overlay.visible = true;
       if (overlay.didShowPage) overlay.didShowPage();
     }
 
     // Update tab title.
     this.setTitle_(overlay.title);
 
+    $('searchBox').setAttribute('aria-hidden', true);
+
     return true;
   };
 
   /**
    * Returns whether or not an overlay is visible.
    * @return {boolean} True if an overlay is visible.
    * @private
    */
   OptionsPage.isOverlayVisible_ = function() {
     return this.getVisibleOverlay_() != null;
@@ skipping 32 matching lines @@
     var overlay = this.getVisibleOverlay_();
     if (!overlay)
       return;
 
     overlay.visible = false;
 
     if (overlay.didClosePage) overlay.didClosePage();
     this.updateHistoryState_(false, {ignoreHash: true});
 
     this.restoreLastFocusedElement_();
+    if (!this.isOverlayVisible_())
+      $('searchBox').removeAttribute('aria-hidden');
   };
 
   /**
    * Cancels (closes) the overlay, due to the user pressing <Esc>.
    */
   OptionsPage.cancelOverlay = function() {
     // Blur the active element to ensure any changed pref value is saved.
     document.activeElement.blur();
     var overlay = this.getVisibleOverlay_();
     // Let the overlay handle the <Esc> if it wants to.
     if (overlay.handleCancel) {
       overlay.handleCancel();
       this.restoreLastFocusedElement_();
     } else {
       this.closeOverlay();
     }
-  }
+  };
 
   /**
    * Hides the visible overlay. Does not affect the history state.
    * @private
    */
   OptionsPage.hideOverlay_ = function() {
     var overlay = this.getVisibleOverlay_();
     if (overlay)
       overlay.visible = false;
   };
@@ skipping 390 matching lines @@
      */
     get visible() {
       // If this is an overlay dialog it is no longer considered visible while
       // the overlay is fading out. See http://crbug.com/118629.
       if (this.isOverlay &&
           this.container.classList.contains('transparent')) {
         return false;
       }
       return !this.pageDiv.hidden;
     },
+
     /**
      * Sets page visibility.
      * @type {boolean}
      */
     set visible(visible) {
       if ((this.visible && visible) || (!this.visible && !visible))
         return;
 
       // If using an overlay, the visibility of the dialog is toggled at the
       // same time as the overlay to show the dialog's out transition. This
@@ skipping 11 matching lines @@
     /**
      * Shows or hides an overlay (including any visible dialog).
      * @param {boolean} visible Whether the overlay should be visible or not.
      * @private
      */
     setOverlayVisible_: function(visible) {
       assert(this.isOverlay);
       var pageDiv = this.pageDiv;
       var container = this.container;
 
-      if (visible)
+      if (visible) {
         uber.invokeMethodOnParent('beginInterceptingEvents');
+        this.pageDiv.removeAttribute('aria-hidden');
+        this.parentPage.pageDiv.setAttribute('aria-hidden', true);
+      } else {
+        this.parentPage.pageDiv.removeAttribute('aria-hidden');
+      }
 
       if (container.hidden != visible) {
         if (visible) {
           // If the container is set hidden and then immediately set visible
           // again, the fadeCompleted_ callback would cause it to be erroneously
           // hidden again. Removing the transparent tag avoids that.
           container.classList.remove('transparent');
 
           // Hide all dialogs in this container since a different one may have
           // been previously visible before fading out.
@@ skipping 101 matching lines @@
     canShowPage: function() {
       return true;
     },
   };
 
   // Export
   return {
     OptionsPage: OptionsPage
   };
 });