app: unexport NewDisplayLink

It's not supposed to be used outside of package app.

Signed-off-by: Elias Naur <mail@eliasnaur.com>

app/os_darwin.go

@@ -124,7 +124,7 @@ func stringToNSString(str string) C.CFTypeRef {
 	return C.newNSString(chars, C.NSUInteger(len(u16)))
 }
 
-func NewDisplayLink(callback func()) (*displayLink, error) {
+func newDisplayLink(callback func()) (*displayLink, error) {
 	d := &displayLink{
 		callback: callback,
 		done:     make(chan struct{}),

app/os_ios.go

@@ -117,7 +117,7 @@ func onCreate(view, controller C.CFTypeRef) {
 	w := &window{
 		view: view,
 	}
-	dl, err := NewDisplayLink(func() {
+	dl, err := newDisplayLink(func() {
 		w.draw(false)
 	})
 	if err != nil {

app/os_macos.go

@@ -886,7 +886,7 @@ func newOSWindow() (*window, error) {
 		scale:  scale,
 		redraw: make(chan struct{}, 1),
 	}
-	dl, err := NewDisplayLink(func() {
+	dl, err := newDisplayLink(func() {
 		select {
 		case w.redraw <- struct{}{}:
 		default: