Implement possibility to hide taskbar icon on Linux

Telegram/SourceFiles/platform/linux/specific_linux.cpp

@@ -502,6 +502,25 @@ bool UnsetXCBFrameExtents(QWindow *window) {
 	return true;
 }
 
+bool XCBSkipTaskbarSupported() {
+	const auto connection = base::Platform::XCB::GetConnectionFromQt();
+	if (!connection) {
+		return false;
+	}
+
+	const auto skipTaskbarAtom = base::Platform::XCB::GetAtom(
+		connection,
+		"_NET_WM_STATE_SKIP_TASKBAR");
+
+	if (!skipTaskbarAtom.has_value()) {
+		return false;
+	}
+
+	return ranges::contains(
+		base::Platform::XCB::GetWMSupported(connection),
+		*skipTaskbarAtom);
+}
+
 Window::Control GtkKeywordToWindowControl(const QString &keyword) {
 	if (keyword == qstr("minimize")) {
 		return Window::Control::Minimize;
@@ -769,6 +788,10 @@ bool TrayIconSupported() {
 		: false;
 }
 
+bool SkipTaskbarSupported() {
+	return !IsWayland() && XCBSkipTaskbarSupported();
+}
+
 bool StartSystemMove(QWindow *window) {
 	if (IsWayland()) {
 		return StartWaylandMove(window);