app: don't discard android touch events of unknown tool type

This is the kind of event one gets when using 'adb shell input tap x y',
which I am trying to use for the end-to-end tests.

Right now, we only have two pointer source types: mouse and touch.
On Android, emulated touch events tend to simulate the touchscreen, not
a mouse, so let's go with that as a fallback.

Perhaps in the future we will have another special pointer source for
this kind of event, such as "unknown" or "virtual".

Signed-off-by: Daniel Martí <mvdan@mvdan.cc>

app/internal/window/os_android.go

@@ -419,6 +419,10 @@ func onTouchEvent(env *C.JNIEnv, class C.jclass, handle C.jlong, action, pointer
 		src = pointer.Touch
 	case C.AMOTION_EVENT_TOOL_TYPE_MOUSE:
 		src = pointer.Mouse
+	case C.AMOTION_EVENT_TOOL_TYPE_UNKNOWN:
+		// For example, triggered via 'adb shell input tap'.
+		// Instead of discarding it, treat it as a touch event.
+		src = pointer.Touch
 	default:
 		return
 	}