Add includes back to channel_info.h.

mojo/edk/system/channel_info.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_EDK_SYSTEM_CHANNEL_INFO_H_
 #define MOJO_EDK_SYSTEM_CHANNEL_INFO_H_
 
 #include "base/memory/ref_counted.h"
+#include "base/task_runner.h"
+#include "mojo/edk/system/channel.h"
 #include "mojo/edk/system/system_impl_export.h"
 
-namespace base {
-class TaskRunner;
-}
-
 namespace mojo {
 namespace system {
 
-class Channel;
-
 struct MOJO_SYSTEM_IMPL_EXPORT ChannelInfo {
   ChannelInfo();
   ChannelInfo(scoped_refptr<Channel> channel,
               scoped_refptr<base::TaskRunner> channel_thread_task_runner);
   ~ChannelInfo();
 
   void Swap(ChannelInfo* other);
 
   scoped_refptr<Channel> channel;
   // The task runner for |channel|'s creation thread (a.k.a. its I/O thread), on
   // which it must, e.g., be shut down.
   scoped_refptr<base::TaskRunner> channel_thread_task_runner;
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_CHANNEL_INFO_H_