Make it possible to write a message pipe endpoint's peer into it.

mojo/edk/system/platform_handle_dispatcher_unittest.cc

 // Copyright 2014 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/platform_handle_dispatcher.h"
 
 #include <stdio.h>
 
 #include <utility>
 
@@ skipping 84 matching lines @@
 
   auto dispatcher =
       PlatformHandleDispatcher::Create(PlatformHandleFromFILE(std::move(fp)));
 
   DispatcherTransport transport(
       test::DispatcherTryStartTransport(dispatcher.get()));
   EXPECT_TRUE(transport.is_valid());
   EXPECT_EQ(Dispatcher::Type::PLATFORM_HANDLE, transport.GetType());
   EXPECT_FALSE(transport.IsBusy());
 
-  auto generic_dispatcher = transport.CreateEquivalentDispatcherAndClose();
+  auto generic_dispatcher =
+      transport.CreateEquivalentDispatcherAndClose(nullptr, 0u);
   ASSERT_TRUE(generic_dispatcher);
 
   transport.End();
   EXPECT_TRUE(dispatcher->HasOneRef());
   dispatcher = nullptr;
 
   ASSERT_EQ(Dispatcher::Type::PLATFORM_HANDLE, generic_dispatcher->GetType());
   dispatcher = RefPtr<PlatformHandleDispatcher>(
       static_cast<PlatformHandleDispatcher*>(generic_dispatcher.get()));
 
   fp = FILEFromPlatformHandle(dispatcher->PassPlatformHandle(), "rb");
   EXPECT_TRUE(fp);
 
   rewind(fp.get());
   char read_buffer[1000] = {};
   EXPECT_EQ(sizeof(kFooBar),
             fread(read_buffer, 1, sizeof(read_buffer), fp.get()));
   EXPECT_STREQ(kFooBar, read_buffer);
 
   EXPECT_EQ(MOJO_RESULT_OK, dispatcher->Close());
 }
 
 }  // namespace
 }  // namespace system
 }  // namespace mojo