io/pointer: remove Foremost priority

The only known use-case (nested scrolling) now works without special
treatment of the foremost handler.

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

io/input/pointer.go

@@ -792,10 +792,8 @@ func (q *pointerQueue) Push(handlers map[event.Tag]*handler, state pointerState,
 }
 
 func (q *pointerQueue) deliverEvent(handlers map[event.Tag]*handler, p pointerInfo, evts []taggedEvent, e pointer.Event) []taggedEvent {
-	foremost := true
 	if p.pressed && len(p.handlers) == 1 {
 		e.Priority = pointer.Grabbed
-		foremost = false
 	}
 	scroll := e.Scroll
 	for _, k := range p.handlers {
@@ -814,10 +812,6 @@ func (q *pointerQueue) deliverEvent(handlers map[event.Tag]*handler, p pointerIn
 			scroll, e.Scroll = f.clampScroll(scroll)
 		}
 		e := e
-		if foremost {
-			foremost = false
-			e.Priority = pointer.Foremost
-		}
 		e.Position = q.invTransform(h.pointer.areaPlusOne-1, e.Position)
 		evts = append(evts, taggedEvent{event: e, tag: k})
 	}

io/input/pointer_test.go

@@ -400,9 +400,9 @@ func TestPointerPriority(t *testing.T) {
 	assertEventPointerTypeSequence(t, hev1, pointer.Scroll, pointer.Scroll)
 	assertEventPointerTypeSequence(t, hev2, pointer.Scroll)
 	assertEventPointerTypeSequence(t, hev3, pointer.Scroll)
-	assertEventPriorities(t, hev1, pointer.Shared, pointer.Foremost)
-	assertEventPriorities(t, hev2, pointer.Foremost)
-	assertEventPriorities(t, hev3, pointer.Foremost)
+	assertEventPriorities(t, hev1, pointer.Shared, pointer.Shared)
+	assertEventPriorities(t, hev2, pointer.Shared)
+	assertEventPriorities(t, hev3, pointer.Shared)
 	assertScrollEvent(t, hev1[0], f32.Pt(30, 0))
 	assertScrollEvent(t, hev2[0], f32.Pt(20, 0))
 	assertScrollEvent(t, hev1[1], f32.Pt(50, 0))
@@ -1143,7 +1143,7 @@ func TestPartialEvent(t *testing.T) {
 		key.FocusEvent{}, pointer.Event{Kind: pointer.Press, Source: pointer.Mouse, Priority: pointer.Shared})
 	r.Source().Execute(key.FocusCmd{Tag: 1})
 	assertEventSequence(t, events(&r, -1, pointer.Filter{Target: 2, Kinds: pointer.Press}),
-		pointer.Event{Kind: pointer.Press, Source: pointer.Mouse, Priority: pointer.Foremost})
+		pointer.Event{Kind: pointer.Press, Source: pointer.Mouse, Priority: pointer.Shared})
 }
 
 // offer satisfies io.ReadCloser for use in data transfers.

io/pointer/pointer.go

@@ -207,9 +207,6 @@ const (
 	// Shared priority is for handlers that
 	// are part of a matching set larger than 1.
 	Shared Priority = iota
-	// Foremost priority is like Shared, but the
-	// handler is the foremost of the matching set.
-	Foremost
 	// Grabbed is used for matching sets of size 1.
 	Grabbed
 )
@@ -295,8 +292,6 @@ func (p Priority) String() string {
 	switch p {
 	case Shared:
 		return "Shared"
-	case Foremost:
-		return "Foremost"
 	case Grabbed:
 		return "Grabbed"
 	default: