[gimp] app: use gimp_tile_handler_validate_validate() in GimpProjection

[Ell <ell src gnome org>]

commit d6f0ca5531e73f8f002b41e700b71a166e5fe5ae
Author: Ell <ell_se yahoo com>
Date:   Wed Nov 28 13:08:57 2018 -0500

    app: use gimp_tile_handler_validate_validate() in GimpProjection
    
    Use gimp_tile_handler_validate_validate(), added in the last
    commit, in GimpProjection, in order to render the projection,
    instead of separately invalidating the buffer, undoing the
    invalidation, and then rendering the graph.  This is more
    efficient, and more idiomatic.

 app/core/gimpprojection.c | 32 ++++++++++++++------------------
 1 file changed, 14 insertions(+), 18 deletions(-)
---
diff --git a/app/core/gimpprojection.c b/app/core/gimpprojection.c
index a42aaea608..0baae20083 100644
--- a/app/core/gimpprojection.c
+++ b/app/core/gimpprojection.c
@@ -736,16 +736,12 @@ gimp_projection_free_buffer (GimpProjection  *proj)
 
   if (proj->priv->buffer)
     {
-      if (proj->priv->validate_handler)
-        {
-          gimp_tile_handler_validate_unassign (proj->priv->validate_handler,
-                                               proj->priv->buffer);
-        }
+      gimp_tile_handler_validate_unassign (proj->priv->validate_handler,
+                                           proj->priv->buffer);
 
       g_clear_object (&proj->priv->buffer);
+      g_clear_object (&proj->priv->validate_handler);
     }
-
-  g_clear_object (&proj->priv->validate_handler);
 }
 
 static void
@@ -1154,19 +1150,19 @@ gimp_projection_paint_area (GimpProjection *proj,
                                 0, 0, width, height,
                                 &x, &y, &w, &h))
     {
-      if (proj->priv->validate_handler)
-        gimp_tile_handler_validate_invalidate (proj->priv->validate_handler,
-                                               GEGL_RECTANGLE (x, y, w, h));
       if (now)
         {
-          GeglNode *graph = gimp_projectable_get_graph (proj->priv->projectable);
-
-          if (proj->priv->validate_handler)
-            gimp_tile_handler_validate_undo_invalidate (proj->priv->validate_handler,
-                                                        GEGL_RECTANGLE (x, y, w, h));
-
-          gegl_node_blit_buffer (graph, proj->priv->buffer,
-                                 GEGL_RECTANGLE (x, y, w, h), 0, GEGL_ABYSS_NONE);
+          gimp_tile_handler_validate_validate (
+            proj->priv->validate_handler,
+            proj->priv->buffer,
+            GEGL_RECTANGLE (x, y, w, h),
+            FALSE);
+        }
+      else
+        {
+          gimp_tile_handler_validate_invalidate (
+            proj->priv->validate_handler,
+            GEGL_RECTANGLE (x, y, w, h));
         }
 
       /*  add the projectable's offsets because the list of update areas