[mutter] Check that the application is responding when activating a window

[Giovanni Campagna <gcampagna src gnome org>]

commit 6431abbc8539c503f8d4dcf56bef9d66dcfe129a
Author: Giovanni Campagna <gcampagna src gnome org>
Date:   Mon Dec 24 18:19:26 2012 +0100

    Check that the application is responding when activating a window
    
    Currently, we ping windows only when attempting to delete them, but
    if the application is not responding, we want to show the dialog
    as soon as possible. Given that we cannot be passively notified that
    the window stopped responding with the current X11 protocol, a good
    workaround is to ping the window when activating it.
    If the window stops responding while active, it is expected the user
    will try to switch window or open the overview, and when coming back
    he'll get the failure dialog.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=684340

 src/core/window.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/core/window.c b/src/core/window.c
index e891bd5..829e12d 100644
--- a/src/core/window.c
+++ b/src/core/window.c
@@ -4247,6 +4247,8 @@ window_activate (MetaWindow     *window,
               "Focusing window %s due to activation\n",
               window->desc);
   meta_window_focus (window, timestamp);
+
+  meta_window_check_alive (window, timestamp);
 }
 
 /* This function exists since most of the functionality in window_activate