Make //mojo/edk/system use //mojo/util's WeakPtr(Factory) instead of base's.

mojo/edk/system/channel_manager.cc

 // 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.
 
 #include "mojo/edk/system/channel_manager.h"
 
 #include <utility>
 
+#include "base/logging.h"
 #include "mojo/edk/platform/platform_handle.h"
 #include "mojo/edk/system/channel.h"
 #include "mojo/edk/system/channel_endpoint.h"
 #include "mojo/edk/system/message_pipe_dispatcher.h"
 
 using mojo::platform::PlatformHandle;
 using mojo::platform::PlatformHandleWatcher;
 using mojo::platform::ScopedPlatformHandle;
 using mojo::platform::TaskRunner;
 using mojo::util::MakeRefCounted;
@@ skipping 165 matching lines @@
     MutexLocker locker(&mutex_);
     CHECK(channels_.find(channel_id) == channels_.end());
     channels_[channel_id] = channel;
   }
   channel->SetChannelManager(this);
   return channel;
 }
 
 }  // namespace system
 }  // namespace mojo