Set the focus ring color to match the Gtk theme focus color.

chrome/common/gtk_util.cc

Index: chrome/common/gtk_util.cc
===================================================================
--- chrome/common/gtk_util.cc	(revision 25076)
+++ chrome/common/gtk_util.cc	(working copy)
@@ -405,6 +405,15 @@
     }
   }
 
+  static GtkWidget* fixed = gtk_fixed_new();
+  GtkStyle* style = gtk_rc_get_style(fixed);
+  // base[SELECTED] seems more appropriate but in practice it is often too light
+  // to be easily visible.
+  GdkColor color = style->bg[GTK_STATE_SELECTED];
+  prefs->focus_ring_color_r = color.red / 257;
+  prefs->focus_ring_color_g = color.green / 257;
+  prefs->focus_ring_color_b = color.blue / 257;
+
   if (hint_style)
     g_free(hint_style);
   if (rgba_style)