Support client initiated window resizing

Closes #185

tests/integration.rs

@@ -2053,3 +2053,33 @@ fn client_init_move() {
     let data = f.testwl.get_surface_data(surface).unwrap();
     assert!(data.moving);
 }
+
+#[test]
+fn client_init_resize() {
+    let mut f = Fixture::new();
+    let mut connection = Connection::new(&f.display);
+
+    let win_toplevel = connection.new_window(connection.root, 0, 0, 20, 20, false);
+    let surface = f.map_as_toplevel(&mut connection, win_toplevel);
+    f.testwl.move_pointer_to(surface, 10., 10.);
+    let ptr = f.testwl.pointer();
+    ptr.motion(10, 10.0, 10.0);
+    ptr.frame();
+    ptr.button(10, 20, BTN_LEFT, wl_pointer::ButtonState::Pressed);
+    ptr.frame();
+    f.testwl.dispatch();
+
+    connection.send_client_message(&x::ClientMessageEvent::new(
+        win_toplevel,
+        connection.atoms.moveresize,
+        x::ClientMessageData::Data32([0, 0, MoveResizeDirection::SizeBottomRight.into(), 1, 0]),
+    ));
+
+    f.wait_and_dispatch();
+    let data = f.testwl.get_surface_data(surface).unwrap();
+    assert!(
+        matches!(data.resizing, Some(xdg_toplevel::ResizeEdge::BottomRight)),
+        "Got wrong resizing edge: {:?}",
+        data.resizing
+    );
+}