blimp: Cleanup class/struct forward declarations

blimp/net/engine_authentication_handler.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 BLIMP_NET_ENGINE_AUTHENTICATION_HANDLER_H_
 #define BLIMP_NET_ENGINE_AUTHENTICATION_HANDLER_H_
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "blimp/net/blimp_net_export.h"
 #include "blimp/net/connection_handler.h"
 
 namespace blimp {
 
 class BlimpConnection;
-class BlimpMessage;
 
 // Authenticates connections and passes successfully authenticated connections
 // to |connection_handler|.
 class BLIMP_NET_EXPORT EngineAuthenticationHandler : public ConnectionHandler {
  public:
   // |client_auth_token|: used to authenticate incoming connection.
   // |connection_handler|: a new connection is passed on to it after the
   //    connection is authenticate this handler.
   EngineAuthenticationHandler(ConnectionHandler* connection_handler,
                               const std::string& client_auth_token);
@@ skipping 10 matching lines @@
   // Used to authenticate incoming connection. Engine is assigned to one client
   // only, and all connections from that client shall carry the same token.
   const std::string client_auth_token_;
 
   DISALLOW_COPY_AND_ASSIGN(EngineAuthenticationHandler);
 };
 
 }  // namespace blimp
 
 #endif  // BLIMP_NET_ENGINE_AUTHENTICATION_HANDLER_H_