Fix GTK redraw artifacts with non html content

svn path=/trunk/netsurf/; revision=10753

gtk/gtk_scaffolding.c

@@ -1373,6 +1373,11 @@ gboolean nsgtk_history_expose_event(GtkWidget *widget,
 	plot = nsgtk_plotters;
 	nsgtk_plot_set_scale(1.0);
 
+	plot.clip(event->area.x, 
+		  event->area.y,	
+		  event->area.x + event->area.width, 
+		  event->area.y + event->area.height);
+
 	history_redraw(bw->history);
 
 	current_widget = NULL;

gtk/gtk_thumbnail.c

@@ -100,6 +100,8 @@ bool thumbnail_create(hlcache_handle *content, struct bitmap *bitmap,
 #endif
 	plot.rectangle(0, 0, cwidth, cwidth, plot_style_fill_white);
 
+	plot.clip(0, 0, content_get_width(content), content_get_width(content));
+
 	/* render the content */
 	content_redraw(content, 0, 0, content_get_width(content), 
 			content_get_width(content),

gtk/gtk_window.c

@@ -408,6 +408,11 @@ gboolean nsgtk_window_expose_event(GtkWidget *widget,
 	nsgtk_plot_set_scale(g->bw->scale);
 	current_redraw_browser = g->bw;
 
+	plot.clip(event->area.x, 
+		  event->area.y,	
+		  event->area.x + event->area.width, 
+		  event->area.y + event->area.height);
+
 	content_redraw(c, 0, 0,
 			widget->allocation.width * scale,
 			widget->allocation.height * scale,