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

mojo/edk/system/dispatcher_unittest.cc

 // 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.
 
 #include "mojo/edk/system/dispatcher.h"
 
 #include <memory>
 
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_vector.h"
@@ skipping 10 matching lines @@
 namespace {
 
 // Trivial subclass that makes the constructor public.
 class TrivialDispatcher final : public Dispatcher {
  public:
   TrivialDispatcher() {}
 
   Type GetType() const override { return Type::UNKNOWN; }
 
  private:
-  friend class base::RefCountedThreadSafe<TrivialDispatcher>;
   ~TrivialDispatcher() override {}
 
   scoped_refptr<Dispatcher> CreateEquivalentDispatcherAndCloseImplNoLock()
       override {
     mutex().AssertHeld();
     return scoped_refptr<Dispatcher>(new TrivialDispatcher());
   }
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(TrivialDispatcher);
 };
@@ skipping 255 matching lines @@
       event.Signal();
     }  // Joins all the threads.
 
     EXPECT_EQ(MOJO_RESULT_OK, d->Close());
   }
 }
 
 }  // namespace
 }  // namespace system
 }  // namespace mojo