Convert mojo::system::Dispatcher to use our new refcounting stuff (instead of base's).

mojo/edk/system/message_pipe_dispatcher.h

Index: mojo/edk/system/message_pipe_dispatcher.h
diff --git a/mojo/edk/system/message_pipe_dispatcher.h b/mojo/edk/system/message_pipe_dispatcher.h
index bfc7997a42ea382ac23a5637b77db185c0a21676..24b262f1dd2b63824069c39e0f2cd0c6536d6672 100644
--- a/mojo/edk/system/message_pipe_dispatcher.h
+++ b/mojo/edk/system/message_pipe_dispatcher.h
@@ -5,7 +5,6 @@
 #ifndef MOJO_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_
 #define MOJO_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_
 
-#include "base/memory/ref_counted.h"
 #include "mojo/edk/system/dispatcher.h"
 #include "mojo/edk/system/memory.h"
 #include "mojo/edk/system/ref_ptr.h"
@@ -27,9 +26,9 @@ class MessagePipeDispatcher final : public Dispatcher {
   // this is exposed directly for testing convenience.)
   static const MojoCreateMessagePipeOptions kDefaultCreateOptions;
 
-  static scoped_refptr<MessagePipeDispatcher> Create(
+  static RefPtr<MessagePipeDispatcher> Create(
       const MojoCreateMessagePipeOptions& /*validated_options*/) {
-    return make_scoped_refptr(new MessagePipeDispatcher());
+    return AdoptRef(new MessagePipeDispatcher());
   }
 
   // Validates and/or sets default options for |MojoCreateMessagePipeOptions|.
@@ -53,14 +52,14 @@ class MessagePipeDispatcher final : public Dispatcher {
   // the message pipe, port 0).
   // TODO(vtl): This currently uses |kDefaultCreateOptions|, which is okay since
   // there aren't any options, but eventually options should be plumbed through.
-  static scoped_refptr<MessagePipeDispatcher> CreateRemoteMessagePipe(
+  static RefPtr<MessagePipeDispatcher> CreateRemoteMessagePipe(
       RefPtr<ChannelEndpoint>* channel_endpoint);
 
   // The "opposite" of |SerializeAndClose()|. (Typically this is called by
   // |Dispatcher::Deserialize()|.)
-  static scoped_refptr<MessagePipeDispatcher> Deserialize(Channel* channel,
-                                                          const void* source,
-                                                          size_t size);
+  static RefPtr<MessagePipeDispatcher> Deserialize(Channel* channel,
+                                                   const void* source,
+                                                   size_t size);
 
  private:
   friend class MessagePipeDispatcherTransport;
@@ -79,8 +78,7 @@ class MessagePipeDispatcher final : public Dispatcher {
   // |Dispatcher| protected methods:
   void CancelAllAwakablesNoLock() override;
   void CloseImplNoLock() override;
-  scoped_refptr<Dispatcher> CreateEquivalentDispatcherAndCloseImplNoLock()
-      override;
+  RefPtr<Dispatcher> CreateEquivalentDispatcherAndCloseImplNoLock() override;
   MojoResult WriteMessageImplNoLock(
       UserPointer<const void> bytes,
       uint32_t num_bytes,