[gtk/gtk-2-24] Force redraw on Mojave and later when processing updates.

[John Ralls <jralls src gnome org>]

commit c505d3fcf8571876fa5767411bbe0229591ce104
Author: John Ralls <jralls ceridwen us>
Date:   Thu Mar 14 21:47:37 2019 -0700

    Force redraw on Mojave and later when processing updates.
    
    Fixes https://gitlab.gnome.org/GNOME/gtk/issues/1479

 gdk/quartz/gdkwindow-quartz.c | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/gdk/quartz/gdkwindow-quartz.c b/gdk/quartz/gdkwindow-quartz.c
index fd6d00f5f7..ab5d7c22ad 100644
--- a/gdk/quartz/gdkwindow-quartz.c
+++ b/gdk/quartz/gdkwindow-quartz.c
@@ -487,6 +487,10 @@ _gdk_windowing_after_process_all_updates (void)
 
       _gdk_quartz_drawable_flush (NULL);
 
+      /* 10.14 needs to be told that the view needs to be redrawn, see
+       * https://gitlab.gnome.org/GNOME/gtk/issues/1479 */
+      if (gdk_quartz_osx_version() >= GDK_OSX_MOJAVE)
+           [[nswindow contentView] setNeedsDisplay:YES];
       [nswindow enableFlushWindow];
       [nswindow flushWindow];
       [nswindow release];