MD Settings: Checks the event target in the language tap event handler

chrome/browser/resources/settings/languages_page/languages_page.js

 // Copyright 2015 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 'settings-languages-page' is the settings page
  * for language and input method settings.
  */
 (function() {
 'use strict';
 
+/**
+ * Regular expression used for filtering out tap events not originating from the
+ * language list item based on the event target's class name.
+ *     e.g. 'dropdown-trigger'
+ * @const {!RegExp}
+ */
+var EVENT_TARGET_REGEX = new RegExp('^dropdown-(trigger|content|item)');
+
 Polymer({
   is: 'settings-languages-page',
 
   properties: {
     /**
      * Preferences state.
      */
     prefs: {
       type: Object,
       notify: true,
@@ skipping 27 matching lines @@
   },
 
   /** @override */
   created: function() {
     this.languageHelper_ = LanguageHelperImpl.getInstance();
   },
 
   /**
    * Handler for clicking a language on the main page, which selects the
    * language as the prospective UI language on Chrome OS and Windows.
-   * @param {!{model: !{item: !LanguageState}}} e
+   * @param {!Event} e The tap event.
    */
   onLanguageTap_: function(e) {
+    // Make sure the event comes from tapping the language itself and not the
+    // options menu, its trigger, or its items.
+    if (EVENT_TARGET_REGEX.test(Polymer.dom(e).localTarget.className))
+      return;
+
     // Only change the UI language on platforms that allow it.
     if ((!cr.isChromeOS && !cr.isWindows) || loadTimeData.getBoolean('isGuest'))
       return;
 
     // Set the prospective UI language. This won't take effect until a restart.
-    if (e.model.item.language.supportsUI)
-      this.languageHelper_.setUILanguage(e.model.item.language.code);
+    var tapEvent = /** @type {!{model: !{item: !LanguageState}}} */(e);
+    if (tapEvent.model.item.language.supportsUI)
+      this.languageHelper_.setUILanguage(tapEvent.model.item.language.code);
   },
 
   /**
    * Handler for enabling or disabling spell check.
    * @param {!{target: Element, model: !{item: !LanguageState}}} e
    */
   onSpellCheckChange_: function(e) {
     this.languageHelper_.toggleSpellCheck(e.model.item.language.code,
                                           e.target.checked);
   },
@@ skipping 240 matching lines @@
    * HACK(michaelpg): This is necessary to show the list when navigating to
    * the sub-page. Remove this function when PolymerElements/neon-animation#60
    * is fixed.
    * @param {string} tagName Name of the element containing the <iron-list>.
    */
   forceRenderList_: function(tagName) {
     this.$$(tagName).$$('iron-list').fire('iron-resize');
   },
 });
 })();