Split out the default definitions of Control.allocate() into a single place.

redo/control.go

@@ -54,3 +54,16 @@ func (w *controldefs) commitResize(c *allocation, d *sizing) {
 func (w *controldefs) getAuxResizeInfo(d *sizing) {
 	w.fgetAuxResizeInfo(d)
 }
+
+// and this is the same across all platforms
+func baseallocate(c *controlbase) func(x int, y int, width int, height int, d *sizing) []*allocation {
+	return func(x int, y int, width int, height int, d *sizing) []*allocation {
+		return []*allocation{&allocation{
+			x:		x,
+			y:		y,
+			width:	width,
+			height:	height,
+			this:		c,
+		}}
+	}
+}

redo/control_darwin.go

@@ -28,16 +28,7 @@ func newControl(id C.id) *controlbase {
 	c.fcontainerHide = func() {
 		C.controlSetHidden(c.id, C.YES)
 	}
-	c.fallocate = func(x int, y int, width int, height int, d *sizing) []*allocation {
-		// TODO split into its own function
-		return []*allocation{&allocation{
-			x:		x,
-			y:		y,
-			width:	width,
-			height:	height,
-			this:		c,
-		}}
-	}
+	c.fallocate = baseallocate(c)
 	c.fpreferredSize = func(d *sizing) (int, int) {
 		// TODO
 		return 64, 32

redo/control_unix.go

@@ -35,16 +35,7 @@ func newControl(widget *C.GtkWidget) *controlbase {
 	c.fcontainerHide = func() {
 		C.gtk_widget_hide(c.widget)
 	}
-	c.fallocate = func(x int, y int, width int, height int, d *sizing) []*allocation {
-		// TODO split into its own function
-		return []*allocation{&allocation{
-			x:		x,
-			y:		y,
-			width:	width,
-			height:	height,
-			this:		c,
-		}}
-	}
+	c.fallocate = baseallocate(c)
 	c.fpreferredSize = func(d *sizing) (int, int) {
 		// GTK+ 3 makes this easy: controls can tell us what their preferred size is!
 		// ...actually, it tells us two things: the "minimum size" and the "natural size".

redo/control_windows.go

@@ -29,16 +29,7 @@ func newControl(class C.LPCWSTR, style C.DWORD, extstyle C.DWORD) *controlbase {
 	c.fcontainerHide = func() {
 		C.ShowWindow(c.hwnd, C.SW_HIDE)
 	}
-	c.fallocate = func(x int, y int, width int, height int, d *sizing) []*allocation {
-		// TODO split into its own function
-		return []*allocation{&allocation{
-			x:		x,
-			y:		y,
-			width:	width,
-			height:	height,
-			this:		c,
-		}}
-	}
+	c.fallocate = baseallocate(c)
 	c.fpreferredSize = func(d *sizing) (int, int) {
 		// TODO
 		return 75, 23