bluetooth: Basic browser tests for chrome://bluetooth-internals.

chrome/browser/resources/bluetooth_internals/bluetooth_internals.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.
 
 /**
  * Javascript for bluetooth_internals.html, served from
  *     chrome://bluetooth-internals/.
  */
 
+// Expose for testing.
+var adapterBroker = null;
+var devices = null;
+
 cr.define('bluetooth_internals', function() {
   function initialize() {
-    var adapterBroker = null;
     adapter_broker.getAdapterBroker()
       .then(function(broker) { adapterBroker = broker; })
       .then(function() { return adapterBroker.getInfo(); })
       .then(function(response) { console.log('adapter', response.info); })
       .then(function() { return adapterBroker.getDevices(); })
       .then(function(response) {
         // Hook up device collection events.
-        var devices = new device_collection.DeviceCollection([]);
+        devices = new device_collection.DeviceCollection([]);
         adapterBroker.addEventListener('deviceadded', function(event) {
           devices.addOrUpdate(event.deviceInfo);
         });
         adapterBroker.addEventListener('devicechanged', function(event) {
           devices.addOrUpdate(event.deviceInfo);
         });
         adapterBroker.addEventListener('deviceremoved', function(event) {
           devices.remove(event.deviceInfo);
         });
 
         response.devices.forEach(devices.addOrUpdate,
                                  devices /* this */);
 
         var deviceTable = new device_table.DeviceTable();
         deviceTable.setDevices(devices);
+        deviceTable.id = 'device-table';
+
         document.body.appendChild(deviceTable);
       })
       .catch(function(error) { console.error(error); });
   }
 
   return {
     initialize: initialize
   };
 
 });
 
 document.addEventListener('DOMContentLoaded', bluetooth_internals.initialize);