Avoid blocking while mapping an X11 window

ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h

Index: ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h
diff --git a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h
index 40933bc596479e6cd9e5a73b8fbe066ef83882fe..0709b365e757955c0113ad9cb733fb394d9afadf 100644
--- a/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h
+++ b/ui/views/widget/desktop_aura/desktop_window_tree_host_x11.h
@@ -275,13 +275,11 @@ class VIEWS_EXPORT DesktopWindowTreeHostX11
 
   ui::X11AtomCache atom_cache_;
 
-  // Is the window mapped to the screen?
+  // Whether the window is mapped with respect to the X11.

[Tom (Use chromium acct), 2016/09/26 17:26:04]

nit: "with respect to the X11" -> "with respect to the X11 server"

   bool window_mapped_;
 
-  // Should we wait for an UnmapNotify before trying to remap the window?
-  // If |wait_for_unmap_| is true, we have sent an XUnmapWindow request to the
-  // server and have yet to receive an UnmapNotify.
-  bool wait_for_unmap_;
+  // Whether the window is visible with respect to Aura.
+  bool is_visible_;
 
   // The bounds of |xwindow_|.
   gfx::Rect bounds_in_pixels_;