Fix memory leak in unittests with new Mojo EDK.

mojo/edk/system/message_pipe_dispatcher.h

 // Copyright 2015 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_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_
 #define MOJO_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_
 
 #include "base/memory/ref_counted.h"
 #include "mojo/edk/embedder/platform_channel_pair.h"
 #include "mojo/edk/system/awakable_list.h"
@@ skipping 177 matching lines @@
 
   // If DispatcherTransport is created. Must be set before lock() is called to
   // avoid deadlocks with RawChannel calling us.
   base::Lock started_transport_;
 
   bool serialized_;
   bool calling_init_;
   bool write_error_;
   // Whether it can be sent after read or write.
   bool transferable_;
+  // Whether CloseImplNoLock has grabbed an extra reference which needs to be
+  // released.
+  bool release_reference_in_close_;
 
   MOJO_DISALLOW_COPY_AND_ASSIGN(MessagePipeDispatcher);
 };
 
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_SYSTEM_MESSAGE_PIPE_DISPATCHER_H_