Migrate <cr-dialog> from PaperDialogBehavior to native <dialog>.

chrome/test/data/webui/settings/fake_bluetooth.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 Fake implementation of chrome.bluetooth for testing.
  */
 cr.define('settings', function() {
   /**
    * Fake of the chrome.bluetooth API.
@@ skipping 45 matching lines @@
     getDevice: assertNotReached,
 
     /** @override */
     getDevices: function(callback) {
       setTimeout(function() {
         callback(this.devices);
       }.bind(this));
     },
 
     /** @override */
-    startDiscovery: assertNotReached,
+    startDiscovery: function(callback) {
+      callback();
+    },
 
     /** @override */
     stopDiscovery: assertNotReached,
 
     /** @override */
     onAdapterStateChanged: new FakeChromeEvent(),
 
     /** @override */
     onDeviceAdded: new FakeChromeEvent(),
 
     /** @override */
     onDeviceChanged: new FakeChromeEvent(),
 
     /** @override */
     onDeviceRemoved: new FakeChromeEvent(),
   };
 
   return {FakeBluetooth: FakeBluetooth};
 });