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

chrome/browser/resources/bluetooth_internals/interfaces.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 Mojo interface helpers, served from
  *     chrome://bluetooth-internals/.
  */
 
 cr.define('interfaces', function() {
   /**
+  * Overriden by tests to give them a chance to setup a fake Mojo browser proxy
+  * before any other code executes.
+  * @return {!Promise} A promise firing once necessary setup has been completed.
+  */
+  var setupFn = window.setupFn || function() { return Promise.resolve(); };
+
+  /**
    * Sets up Mojo interfaces and adds them to window.interfaces.
    * @return {Promise}
    */
   function setupInterfaces() {
-    return importModules([
-      'content/public/renderer/frame_interfaces',
-      'device/bluetooth/public/interfaces/adapter.mojom',
-      'device/bluetooth/public/interfaces/device.mojom',
-      'mojo/public/js/connection',
-    ]).then(function([frameInterfaces, bluetoothAdapter, bluetoothDevice,
-        connection]) {
-      interfaces.BluetoothAdapter = bluetoothAdapter;
-      interfaces.BluetoothDevice = bluetoothDevice;
-      interfaces.Connection = connection;
-      interfaces.FrameInterfaces = frameInterfaces;
+    return setupFn().then(function() {
+      return importModules([
+        'content/public/renderer/frame_interfaces',
+        'device/bluetooth/public/interfaces/adapter.mojom',
+        'device/bluetooth/public/interfaces/device.mojom',
+        'mojo/public/js/connection',
+      ]).then(function([frameInterfaces, bluetoothAdapter, bluetoothDevice,
+          connection]) {
+        interfaces.BluetoothAdapter = bluetoothAdapter;
+        interfaces.BluetoothDevice = bluetoothDevice;
+        interfaces.Connection = connection;
+        interfaces.FrameInterfaces = frameInterfaces;
+      });
     });
   }
 
   return {
     setupInterfaces: setupInterfaces,
   };
 });