[mutter] clutter/paint-context: Add API to get base framebuffer

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 5c68596744b49188046139e49ae63d80287f6195
Author: Jonas Ådahl <jadahl gmail com>
Date:   Thu Nov 21 21:28:36 2019 +0100

    clutter/paint-context: Add API to get base framebuffer
    
    This corresponds to the framebuffer the paint targets. For regular stage
    redraws, this means the framebuffer of the stage view.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/935

 clutter/clutter/clutter-paint-context-private.h | 2 ++
 clutter/clutter/clutter-paint-context.c         | 6 ++++++
 2 files changed, 8 insertions(+)
---
diff --git a/clutter/clutter/clutter-paint-context-private.h b/clutter/clutter/clutter-paint-context-private.h
index bb9118019..ba6b68927 100644
--- a/clutter/clutter/clutter-paint-context-private.h
+++ b/clutter/clutter/clutter-paint-context-private.h
@@ -29,4 +29,6 @@ void clutter_paint_context_pop_framebuffer (ClutterPaintContext *paint_context);
 
 gboolean clutter_paint_context_is_drawing_off_stage (ClutterPaintContext *paint_context);
 
+CoglFramebuffer * clutter_paint_context_get_base_framebuffer (ClutterPaintContext *paint_context);
+
 #endif /* CLUTTER_PAINT_CONTEXT_PRIVATE_H */
diff --git a/clutter/clutter/clutter-paint-context.c b/clutter/clutter/clutter-paint-context.c
index fe0b6a6a0..1787435de 100644
--- a/clutter/clutter/clutter-paint-context.c
+++ b/clutter/clutter/clutter-paint-context.c
@@ -129,6 +129,12 @@ clutter_paint_context_get_framebuffer (ClutterPaintContext *paint_context)
   return paint_context->framebuffers->data;
 }
 
+CoglFramebuffer *
+clutter_paint_context_get_base_framebuffer (ClutterPaintContext *paint_context)
+{
+  return g_list_last (paint_context->framebuffers)->data;
+}
+
 /**
  * clutter_paint_context_get_stage_view: (skip)
  */