GUI2/Canvas: removed surface_lock objects

The canvas surface isn't even passed to these functions anymore so I have no idea how this built.

src/gui/core/canvas.cpp

@@ -710,8 +710,6 @@ void rectangle_shape::draw(
 	      && y     <  canvas_h
 	      && y + h <= canvas_h, _("Rectangle doesn't fit on canvas."));
 
-	surface_lock locker(canvas);
-
 	const color_t fill_color = fill_color_(variables);
 
 	// Fill the background, if applicable
@@ -827,8 +825,6 @@ void round_rectangle_shape::draw(
 		&& y     <  canvas_h
 		&& y + h <= canvas_h, _("Rounded Rectangle doesn't fit on canvas."));
 
-	surface_lock locker(canvas);
-
 	const color_t fill_color = fill_color_(variables);
 
 	// Fill the background, if applicable
@@ -956,9 +952,6 @@ void circle_shape::draw(
 			formatter() << "y = " << y << ", radius = " << radius
 						 << "', canvas height = " << canvas_h << ".");
 
-	// lock the surface
-	surface_lock locker(canvas);
-
 	const color_t fill_color = fill_color_(variables);
 	if(!fill_color.null() && radius) {
 		fill_circle(canvas_w, canvas_h, renderer, fill_color, x, y, radius);