remoting: Cleanup class/struct fwd declarations

remoting/test/connection_time_observer.h

 // 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.
 
 #ifndef REMOTING_TEST_CONNECTION_TIME_OBSERVER_H_
 #define REMOTING_TEST_CONNECTION_TIME_OBSERVER_H_
 
 #include <map>
 
 #include "base/macros.h"
 #include "remoting/test/remote_connection_observer.h"
 
 namespace base {
 class TimeDelta;
-class Timer;
 }
 
 namespace remoting {
 namespace test {
 
 // Observes and saves the times when a chromoting client changes its state. It
 // allows for tests to access latency times between the different states the
 // client transitioned through.
 class ConnectionTimeObserver
     : public RemoteConnectionObserver {
@@ skipping 27 matching lines @@
   std::map<protocol::ConnectionToHost::State, base::TimeTicks>
       transition_times_map_;
 
   DISALLOW_COPY_AND_ASSIGN(ConnectionTimeObserver);
 };
 
 }  // namespace test
 }  // namespace remoting
 
 #endif  // REMOTING_TEST_CONNECTION_TIME_OBSERVER_H_