Make mojo_system static and mojo_system_impl a component, never use both

mojo/system/message_pipe.h

 // Copyright 2013 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_SYSTEM_MESSAGE_PIPE_H_
 #define MOJO_SYSTEM_MESSAGE_PIPE_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
 #include "mojo/public/c/system/core.h"
 #include "mojo/system/dispatcher.h"
 #include "mojo/system/message_in_transit.h"
 #include "mojo/system/message_pipe_endpoint.h"
 #include "mojo/system/system_impl_export.h"
 
 namespace mojo {
 namespace system {
 
 class Channel;
 class Waiter;
 
 // |MessagePipe| is the secondary object implementing a message pipe (see the
-// explanatory comment in core_impl.cc). It is typically owned by the
-// dispatcher(s) corresponding to the local endpoints. This class is
-// thread-safe.
+// explanatory comment in core.cc). It is typically owned by the dispatcher(s)
+// corresponding to the local endpoints. This class is thread-safe.
 class MOJO_SYSTEM_IMPL_EXPORT MessagePipe :
     public base::RefCountedThreadSafe<MessagePipe> {
  public:
   MessagePipe(scoped_ptr<MessagePipeEndpoint> endpoint0,
               scoped_ptr<MessagePipeEndpoint> endpoint1);
 
   // Convenience constructor that constructs a |MessagePipe| with two new
   // |LocalMessagePipeEndpoint|s.
   MessagePipe();
 
@@ skipping 59 matching lines @@
   base::Lock lock_;  // Protects the following members.
   scoped_ptr<MessagePipeEndpoint> endpoints_[2];
 
   DISALLOW_COPY_AND_ASSIGN(MessagePipe);
 };
 
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_SYSTEM_MESSAGE_PIPE_H_