Disables the ability to tab to navigation items when an overlay is displayed.

chrome/browser/resources/uber/uber.js

Index: chrome/browser/resources/uber/uber.js
diff --git a/chrome/browser/resources/uber/uber.js b/chrome/browser/resources/uber/uber.js
index c46a82137592b2e0859c425b8ff24cd550aa17b9..cf6cc80230d42f2ccedc19faa8393268d8a9ac71 100644
--- a/chrome/browser/resources/uber/uber.js
+++ b/chrome/browser/resources/uber/uber.js
@@ -151,6 +151,7 @@ cr.define('uber', function() {
    */
   function backgroundNavigation() {
     navFrame.classList.add('background');
+    setNavigationItemTabbing(false);
   }
 
   /**
@@ -158,6 +159,7 @@ cr.define('uber', function() {
    */
   function foregroundNavigation() {
     navFrame.classList.remove('background');
+    setNavigationItemTabbing(true);
   }
 
   /**
@@ -330,6 +332,18 @@ cr.define('uber', function() {
     uber.invokeMethodOnWindow(iframe.contentWindow, 'mouseWheel', params);
   }
 
+  /**
+   * Enables or disables the ability to tab to the navigation items.
+   * @param {boolean} enabled If true, enables tabbing; if false, disables it.
+   */
+  function setNavigationItemTabbing(enabled) {

[Evan Stade, 2012/05/08 23:51:31]

I don't think this function is necessary. Just split the relevant parts into
background/foregroundNavigation

[Kyle Horimoto, 2012/05/09 00:02:19]

Done.

+    navFrame.firstChild.tabIndex = enabled ? 0 : -1;
+    if (enabled)
+      navFrame.firstChild.removeAttribute('aria-hidden');
+    else
+      navFrame.firstChild.setAttribute('aria-hidden', true);
+  }
+
   return {
     onLoad: onLoad,
     onPopHistoryState: onPopHistoryState