MD Settings: Update some dialogs to accept Enter key.

chrome/browser/resources/settings/search_engines_page/search_engine_dialog.js

 // Copyright 2016 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-search-engine-dialog' is a component for adding
  * or editing a search engine entry.
  */
 Polymer({
   is: 'settings-search-engine-dialog',
@@ skipping 74 matching lines @@
   },
 
   /** @private */
   onActionButtonTap_: function() {
     this.browserProxy_.searchEngineEditCompleted(
         this.searchEngine_, this.keyword_, this.queryUrl_);
     this.$.dialog.close();
   },
 
   /**
+   * @param {!KeyboardEvent} e
+   * @private
+   */
+  onKeypress_: function(e) {
+    if (e.key == 'Enter' && !this.$.actionButton.disabled)
+      this.onActionButtonTap_();
+  },
+
+  /**
    * @param {!Event} event
    * @private
    */
   validate_: function(event) {
     var inputElement = Polymer.dom(event).localTarget;
 
     // If element is empty, disable the action button, but don't show the red
     // invalid message.
     if (inputElement.value == '') {
       inputElement.invalid = false;
@@ skipping 11 matching lines @@
   /** @private */
   updateActionButtonState_: function() {
     var allValid = [
       this.$.searchEngine, this.$.keyword, this.$.queryUrl
     ].every(function(inputElement) {
       return !inputElement.invalid && inputElement.value.length > 0;
     });
     this.$.actionButton.disabled = !allValid;
   },
 });