[sysprof/wip/visualizers] visualizer-ticks: use color from GtkStyleContext

[Christian Hergert <chergert src gnome org>]

commit fa1a8d9276ab2a13d69e0c88b0207bc5e3b12345
Author: Christian Hergert <chergert redhat com>
Date:   Tue Sep 27 17:21:28 2016 -0700

    visualizer-ticks: use color from GtkStyleContext
    
    This should improve the coloring when used with a dark theme.

 lib/sp-visualizer-ticks.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)
---
diff --git a/lib/sp-visualizer-ticks.c b/lib/sp-visualizer-ticks.c
index e2eeeb6..a1ffe83 100644
--- a/lib/sp-visualizer-ticks.c
+++ b/lib/sp-visualizer-ticks.c
@@ -99,8 +99,11 @@ sp_visualizer_ticks_draw (GtkWidget *widget,
                           cairo_t   *cr)
 {
   SpVisualizerTicks *self = (SpVisualizerTicks *)widget;
+  GtkStyleContext *style;
   GtkAllocation alloc;
+  GtkStateFlags state;
   gint64 timespan;
+  GdkRGBA color;
 
   g_assert (SP_IS_VISUALIZER_TICKS (self));
   g_assert (cr != NULL);
@@ -110,7 +113,11 @@ sp_visualizer_ticks_draw (GtkWidget *widget,
 
   gtk_widget_get_allocation (GTK_WIDGET (self), &alloc);
 
-  cairo_set_source_rgba (cr, 0, 0, 0, .2);
+  style = gtk_widget_get_style_context (widget);
+  state = gtk_widget_get_state_flags (widget);
+  gtk_style_context_get_color (style, state, &color);
+
+  gdk_cairo_set_source_rgba (cr, &color);
 
   /*
    * We need to discover up to what level we will draw tick marks.