shell-drawing: remove shell_draw_box_pointer()

This was originally done in C because it used cairo, but that can be
done from JS now. Since it was only used by altTab.js, move it there.

https://bugzilla.gnome.org/show_bug.cgi?id=642059

js/ui/altTab.js

@@ -527,16 +527,11 @@ SwitcherList.prototype = {
         this._leftArrow = new St.DrawingArea({ style_class: 'switcher-arrow',
                                                pseudo_class: 'highlighted' });
         this._leftArrow.connect('repaint', Lang.bind(this,
-                                            function (area) {
-                                                Shell.draw_box_pointer(area, Shell.PointerDirection.LEFT);
-                                            }));
-
+            function() { _drawArrow(this._leftArrow, St.Side.LEFT); }));
         this._rightArrow = new St.DrawingArea({ style_class: 'switcher-arrow',
                                                 pseudo_class: 'highlighted' });
         this._rightArrow.connect('repaint', Lang.bind(this,
-                                            function (area) {
-                                                Shell.draw_box_pointer(area, Shell.PointerDirection.RIGHT);
-                                            }));
+            function() { _drawArrow(this._rightArrow, St.Side.RIGHT); }));
 
         this.actor.add_actor(this._leftArrow);
         this.actor.add_actor(this._rightArrow);
@@ -992,10 +987,7 @@ AppSwitcher.prototype = {
 
         let n = this._arrows.length;
         let arrow = new St.DrawingArea({ style_class: 'switcher-arrow' });
-        arrow.connect('repaint', Lang.bind(this,
-            function (area) {
-                Shell.draw_box_pointer(area, Shell.PointerDirection.DOWN);
-            }));
+        arrow.connect('repaint', function() { _drawArrow(arrow, St.Side.BOTTOM); });
         this._list.add_actor(arrow);
         this._arrows.push(arrow);
 
@@ -1101,3 +1093,48 @@ ThumbnailList.prototype = {
         this._thumbnailBins = new Array();
     }
 };
+
+function _drawArrow(area, side) {
+    let themeNode = area.get_theme_node();
+    let borderColor = new Clutter.Color();
+    themeNode.get_border_color(side, borderColor);
+    let bodyColor = new Clutter.Color();
+    themeNode.get_foreground_color(bodyColor);
+
+    let [width, height] = area.get_surface_size ();
+    let cr = area.get_context();
+
+    cr.setLineWidth(1.0);
+    Clutter.cairo_set_source_color(cr, borderColor);
+
+    switch (side) {
+    case St.Side.TOP:
+        cr.moveTo(0, height);
+        cr.lineTo(Math.floor(width * 0.5), 0);
+        cr.lineTo(width, height);
+        break;
+
+    case St.Side.BOTTOM:
+        cr.moveTo(width, 0);
+        cr.lineTo(Math.floor(width * 0.5), height);
+        cr.lineTo(0, 0);
+        break;
+
+    case St.Side.LEFT:
+        cr.moveTo(width, height);
+        cr.lineTo(0, Math.floor(height * 0.5));
+        cr.lineTo(width, 0);
+        break;
+
+    case St.Side.RIGHT:
+        cr.moveTo(0, 0);
+        cr.lineTo(width, Math.floor(height * 0.5));
+        cr.lineTo(0, height);
+        break;
+    }
+
+    cr.strokePreserve();
+
+    Clutter.cairo_set_source_color(cr, bodyColor);
+    cr.fill();
+}

src/shell-drawing.c

@@ -48,61 +48,3 @@ shell_draw_clock (StDrawingArea       *area,
                  yc + minute_radius * sin (angle));
   cairo_stroke (cr);
 }
-
-void
-shell_draw_box_pointer (StDrawingArea         *area,
-                        ShellPointerDirection  direction)
-{
-  StThemeNode *theme_node;
-  ClutterColor border_color, body_color;
-  guint width, height;
-  cairo_t *cr;
-
-  theme_node = st_widget_get_theme_node (ST_WIDGET (area));
-  st_theme_node_get_border_color (theme_node, (StSide)direction, &border_color);
-  st_theme_node_get_foreground_color (theme_node, &body_color);
-
-  st_drawing_area_get_surface_size (area, &width, &height);
-
-  cr = st_drawing_area_get_context (area);
-
-  cairo_set_line_width (cr, 1.0);
-
-  clutter_cairo_set_source_color (cr, &border_color);
-
-  switch (direction)
-    {
-    case SHELL_POINTER_UP:
-      cairo_move_to (cr, 0, height);
-      cairo_line_to (cr, floor (width * 0.5), 0);
-      cairo_line_to (cr, width, height);
-      break;
-
-    case SHELL_POINTER_DOWN:
-      cairo_move_to (cr, width, 0);
-      cairo_line_to (cr, floor (width * 0.5), height);
-      cairo_line_to (cr, 0, 0);
-      break;
-
-    case SHELL_POINTER_LEFT:
-      cairo_move_to (cr, width, height);
-      cairo_line_to (cr, 0, floor (height * 0.5));
-      cairo_line_to (cr, width, 0);
-      break;
-
-    case SHELL_POINTER_RIGHT:
-      cairo_move_to (cr, 0, 0);
-      cairo_line_to (cr, width, floor (height * 0.5));
-      cairo_line_to (cr, 0, height);
-      break;
-
-    default:
-      g_assert_not_reached();
-    }
-
-  cairo_stroke_preserve (cr);
-
-  clutter_cairo_set_source_color (cr, &body_color);
-
-  cairo_fill (cr);
-}

src/shell-drawing.h

@@ -8,17 +8,6 @@
 
 G_BEGIN_DECLS
 
-/* Note that these correspond to StSide */
-typedef enum {
-  SHELL_POINTER_UP,
-  SHELL_POINTER_RIGHT,
-  SHELL_POINTER_DOWN,
-  SHELL_POINTER_LEFT
-} ShellPointerDirection;
-
-void shell_draw_box_pointer (StDrawingArea         *area,
-                             ShellPointerDirection  direction);
-
 void shell_draw_clock (StDrawingArea       *area,
 	               int                  hour,
 	               int                  minute);