blimp: Cleanup class/struct forward declarations

blimp/net/blimp_message_multiplexer.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_BLIMP_MESSAGE_MULTIPLEXER_H_
 #define BLIMP_NET_BLIMP_MESSAGE_MULTIPLEXER_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "blimp/common/proto/blimp_message.pb.h"
 #include "blimp/net/blimp_net_export.h"
 
 namespace blimp {
 
-class BlimpConnection;
 class BlimpMessageProcessor;
 
 // Creates MessageProcessors that receive outgoing messages and put them
 // onto a multiplexed message stream.
 // BlimpMessageMultiplexer is created on the UI thread, and then used and
 // destroyed on the IO thread.
 class BLIMP_NET_EXPORT BlimpMessageMultiplexer {
  public:
   // |output_processor|: A pointer to the MessageProcessor that will receive the
   // multiplexed message stream.
   explicit BlimpMessageMultiplexer(BlimpMessageProcessor* output_processor);
 
   ~BlimpMessageMultiplexer();
 
   // Creates a BlimpMessageProcessor object for sending messages of type
   // |feature_case|. Any number of senders can be created at a time for a given
   // type.
   std::unique_ptr<BlimpMessageProcessor> CreateSender(
       BlimpMessage::FeatureCase feature_case);
 
  private:
   base::WeakPtrFactory<BlimpMessageProcessor> output_weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BlimpMessageMultiplexer);
 };
 
 }  // namespace blimp
 
 #endif  // BLIMP_NET_BLIMP_MESSAGE_MULTIPLEXER_H_