WebUI: For cr-dialog, make Enter click the action-button, if it exists.

ui/webui/resources/cr_elements/cr_dialog/cr_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 'cr-dialog' is a component for showing a modal dialog. If the
  * dialog is closed via close(), a 'close' event is fired. If the dialog is
  * canceled via cancel(), a 'cancel' event is fired followed by a 'close' event.
  * Additionally clients can inspect the dialog's |returnValue| property inside
  * the 'close' event listener to determine whether it was canceled or just
@@ skipping 12 matching lines @@
 
     /**
      * True if the dialog should remain open on 'popstate' events. This is used
      * for navigable dialogs that have their separate navigation handling code.
      */
     ignorePopstate: {
       type: Boolean,
       value: false,
     },
 
+    /**
+     * True if the dialog should ignore 'Enter' keypresses.
+     */
+    ignoreEnterKey: {
+      type: Boolean,
+      value: false,
+    },
+
     showScrollBorders: {
       type: Boolean,
       value: false,
       reflectToAttribute: true,
     },
   },
 
   /** @private {?IntersectionObserver} */
   intersectionObserver_: null,
 
   /** @override */
   ready: function() {
     // If the active history entry changes (i.e. user clicks back button),
     // all open dialogs should be cancelled.
     window.addEventListener('popstate', function() {
       if (!this.ignorePopstate && this.open)
         this.cancel();
     }.bind(this));
+
+    if (!this.ignoreEnterKey)
+      this.addEventListener('keypress', this.onKeypress_.bind(this));
   },
 
   /** @override */
   attached: function() {
     if (this.showScrollBorders) {
       var bodyContainer = this.$$('.body-container');
 
       var callback = function(entries) {
         assert(entries.length == 1);
         bodyContainer.classList.toggle(
@@ skipping 28 matching lines @@
    * @override
    */
   close: function(opt_returnValue) {
     HTMLDialogElement.prototype.close.call(this, 'success');
   },
 
   /** @return {!PaperIconButtonElement} */
   getCloseButton: function() {
     return this.$.close;
   },
+
+  /**
+   * @param {!Event} e
+   * @private
+   */
+  onKeypress_: function(e) {
+    if (e.target != this)
+      return;
+    if (e.key != 'Enter')
+      return;
+
+    var actionButton = this.querySelector('.action-button');
+    if (actionButton && !actionButton.disabled) {
+      actionButton.click();
+      e.preventDefault();
+    }
+  },
 });