[gnome-builder] source-view: add assertions

[Christian Hergert <chergert src gnome org>]

commit 7587d69187a767bdb667ab1a68ec8b4cd4faaeeb
Author: Christian Hergert <christian hergert me>
Date:   Mon Oct 20 21:17:45 2014 -0700

    source-view: add assertions

 src/editor/gb-source-view.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/editor/gb-source-view.c b/src/editor/gb-source-view.c
index 037383d..99c1b4b 100644
--- a/src/editor/gb-source-view.c
+++ b/src/editor/gb-source-view.c
@@ -1333,6 +1333,9 @@ gb_source_view_draw_layer (GtkTextView     *text_view,
                            GtkTextViewLayer layer,
                            cairo_t         *cr)
 {
+  g_assert (GTK_IS_TEXT_VIEW (text_view));
+  g_assert (cr);
+
   g_signal_emit (text_view, gSignals [DRAW_LAYER], 0, layer, cr);
 }