[gnome-desktop] gnome-rr: add a method to discover when underscanning is supported

[Cosimo Cecchi <cosimoc src gnome org>]

commit 6ca97207ad94316783bd8a7b605192caa7a95f0b
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Wed Jul 1 18:03:04 2015 -0700

    gnome-rr: add a method to discover when underscanning is supported
    
    So that the control center will be able to hide/show a checkbox
    accordingly when the hardware supports it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=751814

 .../gnome-desktop3/gnome-desktop3-sections.txt     |    1 +
 libgnome-desktop/gnome-rr.c                        |   10 ++++++++++
 libgnome-desktop/gnome-rr.h                        |    1 +
 3 files changed, 12 insertions(+), 0 deletions(-)
---
diff --git a/docs/reference/gnome-desktop3/gnome-desktop3-sections.txt 
b/docs/reference/gnome-desktop3/gnome-desktop3-sections.txt
index 0527ccd..ecb2b4f 100644
--- a/docs/reference/gnome-desktop3/gnome-desktop3-sections.txt
+++ b/docs/reference/gnome-desktop3/gnome-desktop3-sections.txt
@@ -292,6 +292,7 @@ gnome_rr_output_can_clone
 gnome_rr_output_list_modes
 gnome_rr_output_get_preferred_mode
 gnome_rr_output_supports_mode
+gnome_rr_output_supports_underscanning
 gnome_rr_output_get_is_primary
 gnome_rr_output_get_backlight
 gnome_rr_output_set_backlight
diff --git a/libgnome-desktop/gnome-rr.c b/libgnome-desktop/gnome-rr.c
index fa6a7e3..84b0a44 100644
--- a/libgnome-desktop/gnome-rr.c
+++ b/libgnome-desktop/gnome-rr.c
@@ -82,6 +82,8 @@ struct GnomeRROutput
     gboolean            is_primary;
     gboolean            is_presentation;
     gboolean            is_underscanning;
+    gboolean            supports_underscanning;
+
     GnomeRRTile         tile_info;
 };
 
@@ -1401,6 +1403,7 @@ output_initialize (GnomeRROutput *output, GVariant *info)
     g_variant_lookup (properties, "primary", "b", &output->is_primary);
     g_variant_lookup (properties, "presentation", "b", &output->is_presentation);
     g_variant_lookup (properties, "underscanning", "b", &output->is_underscanning);
+    g_variant_lookup (properties, "supports-underscanning", "b", &output->supports_underscanning);
 
     if ((edid = g_variant_lookup_value (properties, "edid", G_VARIANT_TYPE ("ay"))))
       {
@@ -2214,6 +2217,13 @@ gnome_rr_output_get_is_underscanning (GnomeRROutput *output)
 }
 
 gboolean
+gnome_rr_output_supports_underscanning (GnomeRROutput *output)
+{
+    g_assert (output != NULL);
+    return output->supports_underscanning;
+}
+
+gboolean
 _gnome_rr_output_get_tile_info (GnomeRROutput *output,
                                GnomeRRTile *tile)
 {
diff --git a/libgnome-desktop/gnome-rr.h b/libgnome-desktop/gnome-rr.h
index 9311f07..1f0e5f9 100644
--- a/libgnome-desktop/gnome-rr.h
+++ b/libgnome-desktop/gnome-rr.h
@@ -173,6 +173,7 @@ gboolean        gnome_rr_output_supports_mode      (GnomeRROutput         *outpu
                                                    GnomeRRMode           *mode);
 gboolean        gnome_rr_output_get_is_primary     (GnomeRROutput         *output);
 gboolean        gnome_rr_output_get_is_underscanning (GnomeRROutput       *output);
+gboolean        gnome_rr_output_supports_underscanning (GnomeRROutput       *output);
 
 /* GnomeRRMode */
 guint32         gnome_rr_mode_get_id               (GnomeRRMode           *mode);