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

mojo/edk/system/data_pipe_producer_dispatcher.h

Index: mojo/edk/system/data_pipe_producer_dispatcher.h
diff --git a/mojo/edk/system/data_pipe_producer_dispatcher.h b/mojo/edk/system/data_pipe_producer_dispatcher.h
index 53fa291da538cdab1db86f0c9d02be04d1e2abcc..aed201f80721a8bc6af0edaec43c5f95fa695b2f 100644
--- a/mojo/edk/system/data_pipe_producer_dispatcher.h
+++ b/mojo/edk/system/data_pipe_producer_dispatcher.h
@@ -7,6 +7,7 @@
 
 #include "base/memory/ref_counted.h"
 #include "mojo/edk/system/dispatcher.h"
+#include "mojo/edk/system/ref_ptr.h"
 #include "mojo/public/cpp/system/macros.h"
 
 namespace mojo {
@@ -24,7 +25,7 @@ class DataPipeProducerDispatcher final : public Dispatcher {
   }
 
   // Must be called before any other methods.
-  void Init(scoped_refptr<DataPipe> data_pipe) MOJO_NOT_THREAD_SAFE;
+  void Init(RefPtr<DataPipe>&& data_pipe) MOJO_NOT_THREAD_SAFE;
 
   // |Dispatcher| public methods:
   Type GetType() const override;
@@ -73,7 +74,7 @@ class DataPipeProducerDispatcher final : public Dispatcher {
   bool IsBusyNoLock() const override;
 
   // This will be null if closed.
-  scoped_refptr<DataPipe> data_pipe_ MOJO_GUARDED_BY(mutex());
+  RefPtr<DataPipe> data_pipe_ MOJO_GUARDED_BY(mutex());
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(DataPipeProducerDispatcher);
 };