X11: Better timestamp handling for _NET_ACTIVE_WINDOW

chrome/browser/process_singleton_posix.cc

Index: chrome/browser/process_singleton_posix.cc
diff --git a/chrome/browser/process_singleton_posix.cc b/chrome/browser/process_singleton_posix.cc
index d5394b857a367f8806f408c9d527cc7f5b53d96e..c877d38bbd47c135761caad09b8560a74de04d77 100644
--- a/chrome/browser/process_singleton_posix.cc
+++ b/chrome/browser/process_singleton_posix.cc
@@ -81,6 +81,7 @@
 #include "base/timer/timer.h"
 #include "build/build_config.h"
 #include "chrome/common/chrome_constants.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/grit/chromium_strings.h"
 #include "chrome/grit/generated_resources.h"
 #include "content/public/browser/browser_thread.h"
@@ -91,6 +92,10 @@
 #include "chrome/browser/ui/process_singleton_dialog_linux.h"
 #endif
 
+#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+#include "ui/events/platform/x11/x11_event_source.h"
+#endif
+
 #if defined(TOOLKIT_VIEWS) && defined(OS_LINUX) && !defined(OS_CHROMEOS)
 #include "ui/views/linux_ui/linux_ui.h"
 #endif
@@ -817,6 +822,13 @@ ProcessSingleton::NotifyResult ProcessSingleton::NotifyOtherProcessWithTimeout(
     base::PlatformThread::Sleep(sleep_interval);
   }
 
+#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+  base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
+      switches::kWmUserTimeMs,
+      base::Uint64ToString(
+          ui::X11EventSource::GetInstance()->UpdateServerTime()));
+#endif
+

[Tom (Use chromium acct), 2016/05/06 20:42:00]

This doesn't seem like the best place to put this.  However, it's the only place
where we know another process exists, and before we actually send the arguments.

Maybe this could be moved to ChromeBrowserMainParts::PreCreateThreadsImpl?  We
would need to call UpdateServerTime anyway when we make the first call to
Activate() since wm_user_time_ms is initialized to 0.  However, then the new
--wm-user-time-ms flag will redundantly set the server time again (although that
shouldn't matter now that we have the new logic in set_wm_user_time_ms)

[Elliot Glaysher, 2016/05/06 21:13:13]

I agree that this is really not a good place for this, and putting this in
something like ChromeBrowserMainExtraPartsX11 would be a better place for this
to live.

[Tom (Use chromium acct), 2016/05/06 22:09:43]

Done.

   timeval socket_timeout = TimeDeltaToTimeVal(timeout);
   setsockopt(socket.fd(),
              SOL_SOCKET,