First cut at mojo spy's websocket server

mojo/spy/spy.h

 // 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.
 
 #ifndef MOJO_SPY_SPY_H_
 #define MOJO_SPY_SPY_H_
 
 #include <string>
+#include "base/memory/scoped_ptr.h"
+
+namespace base {
+ class Thread;
+}
 
 namespace mojo {
 
 class ServiceManager;
 
+// mojo::Spy is a troubleshooting and debugging aid. It helps tracking
+// the mojo system core activities like messages, service creation, etc.
+//
+// The |options| parameter in the constructor comes from the command
+// line of the mojo_shell. Which takes --spy=<options>. Each option is
+// separated by ',' and each option is a key+ value pair separated by ':'.
+//
+// For example --spy=port:13333
+//
 class Spy {
  public:
   Spy(mojo::ServiceManager* service_manager, const std::string& options);
   ~Spy();
+
+ private:
+   // This thread runs the code that talks to the frontend.
+   scoped_ptr<base::Thread> control_thread_;
 };
 
 }  // namespace mojo
 
 #endif  // MOJO_SPY_SPY_H_