[Chromoting] Enable jscompile for webapp unittests.

remoting/webapp/unittests/it2me_helper_channel_unittest.js

 // Copyright 2014 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
+ * @suppress {checkTypes|checkVars|reportUnknownTypes|visibility}
+ */
+
 (function() {
 
 'use strict';
 
 var appLauncher = null;
 var hangoutPort = null;
 var webappPort = null;
 var helperChannel = null;
 var disconnectCallback = null;
 
@@ skipping 165 matching lines @@
   hangoutPort.onDisconnect.mock$fire();
 
   sinon.assert.calledOnce(appLauncher.close);
   sinon.assert.calledOnce(disconnectCallback);
 
   sinon.assert.called(hangoutPort.disconnect);
   sinon.assert.called(webappPort.disconnect);
 });
 
 })();