EDK: Add Core::DuplicateHandleWithReducedRights().

mojo/edk/system/shared_buffer_dispatcher.cc

Index: mojo/edk/system/shared_buffer_dispatcher.cc
diff --git a/mojo/edk/system/shared_buffer_dispatcher.cc b/mojo/edk/system/shared_buffer_dispatcher.cc
index 903d338c3fd1e92995c924aa82564e4ffb5a9fd2..af3ed3161d33acf6daa449ec86e727887a780c26 100644
--- a/mojo/edk/system/shared_buffer_dispatcher.cc
+++ b/mojo/edk/system/shared_buffer_dispatcher.cc
@@ -219,6 +219,15 @@ void SharedBufferDispatcher::CloseImplNoLock() {
   shared_buffer_ = nullptr;
 }
 
+MojoResult SharedBufferDispatcher::DuplicateDispatcherImplNoLock(
+    util::RefPtr<Dispatcher>* new_dispatcher) {
+  mutex().AssertHeld();
+
+  // Note: Since this is "duplicate", we keep our ref to |shared_buffer_|.
+  *new_dispatcher = CreateInternal(shared_buffer_.Clone());
+  return MOJO_RESULT_OK;
+}
+
 RefPtr<Dispatcher>
 SharedBufferDispatcher::CreateEquivalentDispatcherAndCloseImplNoLock(
     MessagePipe* /*message_pipe*/,