xwayland: Respect client WM_TAKE_FOCUS setting

According to https://tronche.com/gui/x/icccm/sec-4.html#s-4.1.7 we should
send this focus notification only if a client has WM_TAKE_FOCUS set in
their WM_PROTOCOLS property. We've been sending it unconditionally.

Rather, we've been not-sending it unconditionally because the event mask
is wrong, but that will be fixed in a future commit. Fixing the event
mask first would break some clients (such as xterm).

Co-authored-by: Steve Pronovost <spronovo@microsoft.com>
Co-authored-by: Brenton DeGeer <brdegeer@microsoft.com>
Signed-off-by: Hideyuki Nagase <hideyukn@microsoft.com>
Signed-off-by: Steve Pronovost <spronovo@microsoft.com>
Signed-off-by: Brenton DeGeer <brdegeer@microsoft.com>

xwayland/window-manager.c

@@ -171,6 +171,7 @@ struct weston_wm_window {
 	int delete_window;
 	int maximized_vert;
 	int maximized_horz;
+	int take_focus;
 	struct wm_size_hints size_hints;
 	struct motif_wm_hints motif_hints;
 	struct wl_list link;
@@ -530,6 +531,7 @@ weston_wm_window_read_properties(struct weston_wm_window *window)
 	window->size_hints.flags = 0;
 	window->motif_hints.flags = 0;
 	window->delete_window = 0;
+	window->take_focus = 0;
 
 	for (i = 0; i < ARRAY_LENGTH(props); i++)  {
 		reply = xcb_get_property_reply(wm->conn, cookie[i], NULL);
@@ -572,7 +574,8 @@ weston_wm_window_read_properties(struct weston_wm_window *window)
 			for (i = 0; i < reply->value_len; i++)
 				if (atom[i] == wm->atom.wm_delete_window) {
 					window->delete_window = 1;
-					break;
+				} else if (atom[i] == wm->atom.wm_take_focus) {
+					window->take_focus = 1;
 				}
 			break;
 		case TYPE_WM_NORMAL_HINTS:
@@ -936,6 +939,7 @@ weston_wm_send_focus_window(struct weston_wm *wm,
 		if (window->override_redirect)
 			return;
 
+		if (window->take_focus) {
 			client_message.response_type = XCB_CLIENT_MESSAGE;
 			client_message.format = 32;
 			client_message.window = window->id;
@@ -946,6 +950,7 @@ weston_wm_send_focus_window(struct weston_wm *wm,
 			xcb_send_event(wm->conn, 0, window->id,
 				       XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT,
 				       (char *) &client_message);
+		}
 
 		xcb_set_input_focus (wm->conn, XCB_INPUT_FOCUS_POINTER_ROOT,
 				     window->id, XCB_TIME_CURRENT_TIME);