Fix ChromeVox's detection of whether the current document has focus.

chrome/browser/resources/chromeos/chromevox/common/chromevox.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.
 
 /**
  * @fileoverview Defines a global object. The initialization of this
  *   object happens in init.js.
  *
  */
 
@@ skipping 257 matching lines @@
  * @return {HTMLElement} with the id.
  */
 function $(id) {
   return document.getElementById(id);
 }
 
 /**
  * @param {Array} tabs
  */
 cvox.ChromeVox.injectChromeVoxIntoTabs = function(tabs) {};
+
+/**
+ * Returns whether the document has focus, taking into account whether
+ * it's hidden and also that if an iframe or webview element has focus,
+ * the focus is really inside that frame and not in this document.
+ * @return {boolean} True if the document has focus.
+ */
+cvox.ChromeVox.documentHasFocus = function() {
+  if (!document.hasFocus() || document.hidden) {
+    return false;
+  }
+  if (document.activeElement.tagName == 'IFRAME' ||
+      document.activeElement.tagName == 'WEBVIEW') {
+    return false;
+  }
+  return true;
+};