chromeos: Cleanup class/struct fwd declarations

chromeos/dbus/services/liveness_service_provider.h

 // Copyright (c) 2012 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 CHROMEOS_DBUS_SERVICES_LIVENESS_SERVICE_PROVIDER_H_
 #define CHROMEOS_DBUS_SERVICES_LIVENESS_SERVICE_PROVIDER_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "chromeos/chromeos_export.h"
 #include "chromeos/dbus/services/cros_dbus_service.h"
 #include "dbus/exported_object.h"
 
 namespace dbus {
 class MethodCall;
-class Response;
 }
 
 namespace chromeos {
 
 // This class exports a "CheckLiveness" D-Bus method that the session manager
 // calls periodically to confirm that Chrome's UI thread is responsive to D-Bus
 // messages.  It can be tested with the following command:
 //
 // % dbus-send --system --type=method_call --print-reply
 //     --dest=org.chromium.LibCrosService
@@ skipping 26 matching lines @@
   // Keep this last so that all weak pointers will be invalidated at the
   // beginning of destruction.
   base::WeakPtrFactory<LivenessServiceProvider> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(LivenessServiceProvider);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROMEOS_DBUS_SERVICES_LIVENESS_SERVICE_PROVIDER_H_