Call preventDefault in all on-tap events that show a dialog.

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 176135ddee39abc4eb272e7c70b04725232763f5..10309a3914834a77d87e6466b2dbaddb6c6469df 100644
--- a/chrome/browser/resources/settings/languages_page/languages_page.js
+++ b/chrome/browser/resources/settings/languages_page/languages_page.js
@@ -68,9 +68,11 @@ Polymer({
   /**
    * Stamps and opens the Add Languages dialog, registering a listener to
    * disable the dialog's dom-if again on close.
+   * @param {!Event} e
    * @private
    */
-  onAddLanguagesTap_: function() {
+  onAddLanguagesTap_: function(e) {
+    e.preventDefault();
     this.showAddLanguagesDialog_ = true;
     this.async(function() {
       var dialog = this.$$('settings-add-languages-dialog');