[Chromoting] Enable jscompile for webapp unittests.

remoting/webapp/js_proto/chrome_event_proto.js

Index: remoting/webapp/js_proto/chrome_event_proto.js
diff --git a/remoting/webapp/js_proto/chrome_event_proto.js b/remoting/webapp/js_proto/chrome_event_proto.js
new file mode 100644
index 0000000000000000000000000000000000000000..317f711f921189444ad4c6d3e7d6154a905908d9
--- /dev/null
+++ b/remoting/webapp/js_proto/chrome_event_proto.js
@@ -0,0 +1,12 @@
+// 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.
+
+/** @constructor */
+chrome.Event = function() {};
+
+/** @param {Function} callback */
+chrome.Event.prototype.addListener = function(callback) {};
+
+/** @param {Function} callback */
+chrome.Event.prototype.removeListener = function(callback) {};