Harmony - convert hung renderer dialog.

chrome/browser/ui/test/browser_dialog_browsertest.cc

 // Copyright 2016 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 "base/command_line.h"
 #include "base/process/launch.h"
 #include "base/test/launcher/test_launcher.h"
 #include "base/test/test_switches.h"
 #include "base/test/test_timeouts.h"
 #include "chrome/browser/ui/test/test_browser_dialog.h"
@@ skipping 48 matching lines @@
 
   base::LaunchOptions options;
 
   // Disable timeouts and generate screen output if --interactive was specified.
   if (command.HasSwitch(internal::kInteractiveSwitch)) {
     command.AppendSwitchASCII(switches::kUiTestActionMaxTimeout,
                               TestTimeouts::kNoTimeoutSwitchValue);
     command.AppendSwitchASCII(switches::kTestLauncherTimeout,
                               TestTimeouts::kNoTimeoutSwitchValue);
     command.AppendSwitch(switches::kEnablePixelOutputInTests);
+#if defined(OS_WIN)
+    options.wait = true;

[Bret, 2017/02/01 00:05:30]

This is the fix for having to pass in --single-process on Windows.

[tapted, 2017/02/01 00:52:48]

Can you comment here?

I don't know too much about how processes spawn on Windows, but I guess it's
something like

// Windows refuses to spawn the child process if the invoking process goes away
too quickly, so always wait. This means the invoker will bring down the
interactive process when it is killed after a timeout.

[Bret, 2017/02/01 02:21:46]

I actually don't know why this is necessary either, I figured it out on
accident. Maybe Peter knows? Added a more generic comment in the meantime.

[Peter Kasting, 2017/02/02 00:32:30]

I don't know either, but it would be good to find out why, in case it indicates
some more subtle bug that we need to fix elsewhere.

Seems like I just saw someone get a refactoring award for MessageLoop stuff, I
wonder if they would know about this?  Otherwise, if you can turn this into a
more detailed technical question, you could try posting on chrome-windows.

[Bret, 2017/02/03 01:47:17]

This is way outside of my wheelhouse, so I'd rather investigate this separately
from this patch. I can revert this change for this patch too if you want but I
figured it was better to put in the workaround right away.

+#endif
   } else {
     options.wait = true;
   }
 
   base::LaunchProcess(command, options);
 }