Bug 1433068 - Reload WidgetstyleCache when theme changes, r=jhorak

MozReview-Commit-ID: 1cZmJNWjS4N

--HG--
extra : rebase_source : 1e9406c2090b19049c37ac21eff11e05e0be2cc9

widget/gtk/gtk3drawing.cpp

@@ -181,6 +181,9 @@ moz_gtk_refresh()
     sCheckboxMetrics.initialized = false;
     sRadioMetrics.initialized = false;
     sToolbarMetrics.initialized = false;
+
+    /* This will destroy all of our widgets */
+    ResetWidgetCache();
 }
 
 gint