[gtk+/gtk-style-context] GtkThemingEngine: Documents that engines must only use this API.

[Carlos Garnacho <carlosg src gnome org>]

commit bc0324a64177c2e28ba75c13d373c1c9a514cea2
Author: Carlos Garnacho <carlosg gnome org>
Date:   Fri Oct 29 14:17:03 2010 -0400

    GtkThemingEngine: Documents that engines must only use this API.
    
    It was a bit unclear in the documentation, even if it was from the
    API POV.

 gtk/gtkthemingengine.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkthemingengine.c b/gtk/gtkthemingengine.c
index ca3b313..8293106 100644
--- a/gtk/gtkthemingengine.c
+++ b/gtk/gtkthemingengine.c
@@ -45,6 +45,10 @@
  * must be created, alongside the CSS file that will reference it, the
  * theming engine would be created as an .so library, and installed in
  * $(gtk-modules-dir)/theming-engines/.
+ *
+ * #GtkThemingEngine<!-- -->s have limited access to the object they are
+ * rendering, the #GtkThemingEngine API has read-only accessors to the
+ * style information contained in the rendered object's #GtkStyleContext.
  */
 
 typedef struct GtkThemingEnginePrivate GtkThemingEnginePrivate;