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

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

Index: chrome/browser/resources/settings/languages_page/languages_page.js
diff --git a/chrome/browser/resources/settings/languages_page/languages_page.js b/chrome/browser/resources/settings/languages_page/languages_page.js
index d88a859349c5fb9a27f7158565ba51ab9dc59325..7aee1aa3ffe1fd40932e852423c8f1e5f3736620 100644
--- a/chrome/browser/resources/settings/languages_page/languages_page.js
+++ b/chrome/browser/resources/settings/languages_page/languages_page.js
@@ -9,6 +9,14 @@
 (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',
 
@@ -56,16 +64,22 @@ Polymer({
   /**
    * 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);
   },
 
   /**