[gtk+] gtkpixelcache: Fix possibly ignoring queued redraw

[Matthias Clasen <matthiasc src gnome org>]

commit fc8be961634a2bf5bd44f1648859f93df62c4f86
Author: Olivier Brunel <jjk jjacky com>
Date:   Tue Nov 5 19:21:28 2013 +0100

    gtkpixelcache: Fix possibly ignoring queued redraw
    
    If a queue_redraw() (invalidating a region, or the whole widget) was
    called from the draw() call, it could get ignored if surface_dirty
    existed, as it would then be updated, but destroyed right at the end of
    the _gtk_pixel_cache_repaint(), leading the next call to
    _gtk_pixel_cache_draw() have its call to repaint() be a no-op
    (since there's no surface_dirty) and then simply draw from (non
    updated) surface.
    
    Signed-off-by: Olivier Brunel <jjk jjacky com>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=711545

 gtk/gtkpixelcache.c |   15 +++++++--------
 1 files changed, 7 insertions(+), 8 deletions(-)
---
diff --git a/gtk/gtkpixelcache.c b/gtk/gtkpixelcache.c
index 2c03330..411a75e 100644
--- a/gtk/gtkpixelcache.c
+++ b/gtk/gtkpixelcache.c
@@ -327,13 +327,15 @@ _gtk_pixel_cache_repaint (GtkPixelCache *cache,
                          gpointer user_data)
 {
   cairo_t *backing_cr;
+  cairo_region_t *region_dirty = cache->surface_dirty;
+  cache->surface_dirty = NULL;
 
   if (cache->surface &&
-      cache->surface_dirty &&
-      !cairo_region_is_empty (cache->surface_dirty))
+      region_dirty &&
+      !cairo_region_is_empty (region_dirty))
     {
       backing_cr = cairo_create (cache->surface);
-      gdk_cairo_region (backing_cr, cache->surface_dirty);
+      gdk_cairo_region (backing_cr, region_dirty);
       cairo_clip (backing_cr);
       cairo_translate (backing_cr,
                       -cache->surface_x - canvas_rect->x - view_rect->x,
@@ -370,11 +372,8 @@ _gtk_pixel_cache_repaint (GtkPixelCache *cache,
       cairo_destroy (backing_cr);
     }
 
-  if (cache->surface_dirty)
-    {
-      cairo_region_destroy (cache->surface_dirty);
-      cache->surface_dirty = NULL;
-    }
+  if (region_dirty)
+    cairo_region_destroy (region_dirty);
 }
 
 static gboolean