[Chromoting] Enable jscompile for webapp unittests.

remoting/webapp/unittests/xmpp_login_handler_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.
 
 (function() {
 
 'use strict';
 
 var testUsername = 'testUsername@gmail.com';
 var testToken = 'testToken';
 
-var sendMessage = null;
-var startTls = null;
-var onHandshakeDone = null;
-var onStanzaStr = null;
-var onError = null;
+/** @type {(sinon.$spy|function(string):void)} */
+var sendMessage = function(msg) {};
+
+/** @type {(sinon.$spy|function():void)} */
+var startTls = function() {};
+
+/** @type {(sinon.$spy|function(string, remoting.XmppStreamParser):void)} */
+var onHandshakeDone = function(name, parser) {};
+
+/** @type {(sinon.$spy|function(remoting.Error, string):void)} */
+var onError = function(error, message) {};
+
+/** @type {remoting.XmppLoginHandler} */
 var loginHandler = null;
 
 module('XmppLoginHandler', {
   setup: function() {
     sendMessage = sinon.spy();
     startTls = sinon.spy();
     onHandshakeDone = sinon.spy();
     onError = sinon.spy();
+
     loginHandler = new remoting.XmppLoginHandler(
-        'google.com', testUsername, testToken, false, sendMessage,
-        startTls, onHandshakeDone, onError);
+        'google.com', testUsername, testToken, false,
+        /** @type {function(string):void} */ (sendMessage),
+        /** @type {function():void} */ (startTls),
+        /** @type {function(string, remoting.XmppStreamParser):void} */
+            (onHandshakeDone),
+        /** @type {function(remoting.Error, string):void} */ (onError));
   }
 });
 
 // Executes handshake base.
 function handshakeBase() {
   loginHandler.start();
 
   sinon.assert.calledWith(startTls);
   startTls.reset();
 
@@ skipping 106 matching lines @@
 
 test('should return UNEXPECTED error when failed to parse stream',
      function() {
   handshakeBase();
   loginHandler.onDataReceived(
       base.encodeUtf8('BAD DATA'));
   sinon.assert.calledWith(onError, remoting.Error.UNEXPECTED);
 });
 
 })();