Fix DCHECK in ipc_perftests

mojo/edk/test/multiprocess_test_helper.h

 // 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.
 
 #ifndef MOJO_EDK_TEST_MULTIPROCESS_TEST_HELPER_H_
 #define MOJO_EDK_TEST_MULTIPROCESS_TEST_HELPER_H_
 
 #include <string>
 
 #include "base/callback.h"
@@ skipping 67 matching lines @@
   // Like |WaitForChildShutdown()|, but returns true on success (exit code of 0)
   // and false otherwise. You probably want to do something like
   // |EXPECT_TRUE(WaitForChildTestShutdown());|.
   bool WaitForChildTestShutdown();
 
   const base::Process& test_child() const { return test_child_.process; }
 
   // Used by macros in mojo/edk/test/mojo_test_base.h to support multiprocess
   // test client initialization.
   static void ChildSetup();
-  static int RunClientMain(const base::Callback<int(MojoHandle)>& main);
+  static int RunClientMain(const base::Callback<int(MojoHandle)>& main,
+                           bool close_pipe_on_exit = true);

[yzshen1, 2017/03/21 16:43:30]

nit: without reading the code, I am not sure who is responsible to close the
pipe, is it |main| or RunClientMain()? Does it make sense to change
|close_pipe_on_exit| to something like |passes_ownership_to_main|?

[Ken Rockot(use gerrit already), 2017/03/21 16:51:31]

Good point. I've changed it to pass_pipe_ownership_to_main and inverted the
usage.

   static int RunClientTestMain(const base::Callback<void(MojoHandle)>& main);
 
   // For use (and only valid) in the child process:
   static mojo::ScopedMessagePipeHandle primordial_pipe;
 
  private:
   // Valid after |StartChild()| and before |WaitForChildShutdown()|.
   base::SpawnChildResult test_child_;
 
   ProcessErrorCallback process_error_callback_;
 
   std::string peer_token_;
 
   DISALLOW_COPY_AND_ASSIGN(MultiprocessTestHelper);
 };
 
 }  // namespace test
 }  // namespace edk
 }  // namespace mojo
 
 #endif  // MOJO_EDK_TEST_MULTIPROCESS_TEST_HELPER_H_