Mojo: Don't try to close the child process handle after WaitForExitCode().

mojo/shell/child_process_host.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/shell/child_process_host.h"
 
 #include "base/base_switches.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/location.h"
@@ skipping 38 matching lines @@
   CHECK(base::PostTaskAndReplyWithResult(
       context_->task_runners()->blocking_pool(),
       FROM_HERE,
       base::Bind(&ChildProcessHost::DoLaunch, base::Unretained(this)),
       base::Bind(&ChildProcessHost::DidLaunch, base::Unretained(this))));
 }
 
 int ChildProcessHost::Join() {
   DCHECK_NE(child_process_handle_, base::kNullProcessHandle);
   int rv = -1;
+  // Note: |WaitForExitCode()| closes the process handle.
   LOG_IF(ERROR, !base::WaitForExitCode(child_process_handle_, &rv))
       << "Failed to wait for child process";
-  base::CloseProcessHandle(child_process_handle_);
   child_process_handle_ = base::kNullProcessHandle;
   return rv;
 }
 
 bool ChildProcessHost::DoLaunch() {
   static const char* kForwardSwitches[] = {
     switches::kTraceToConsole,
     switches::kV,
     switches::kVModule,
   };
@@ skipping 24 matching lines @@
   platform_channel_pair_.ChildProcessLaunched();
   return true;
 }
 
 void ChildProcessHost::DidLaunch(bool success) {
   delegate_->DidStart(success);
 }
 
 }  // namespace shell
 }  // namespace mojo