WindowServer: Add a custom window type for Launcher

This keeps it out of the taskbar window list.
The stacking order is a little gnarly, but it seems to work OK still.

Applications/Launcher/main.cpp

@@ -72,6 +72,7 @@ GWindow* make_launcher_window()
     int launcher_size = (config->groups().size() - 1) * 50;
     window->set_rect(50, 50, vertical ? 50 : launcher_size, vertical ? launcher_size : 50);
     window->set_show_titlebar(false);
+    window->set_window_type(GWindowType::Launcher);
 
     auto* widget = new GWidget;
     widget->set_fill_with_background_color(true);

Libraries/LibGUI/GWindowType.h

@@ -1,5 +1,6 @@
 #pragma once
 
+// Keep this in sync with WSWindowType.
 enum class GWindowType {
     Invalid = 0,
     Normal,
@@ -7,4 +8,6 @@ enum class GWindowType {
     WindowSwitcher,
     Taskbar,
     Tooltip,
+    Menubar,
+    Launcher,
 };

Servers/WindowServer/WSAPITypes.h

@@ -28,6 +28,7 @@ enum WSAPI_WindowType {
     Taskbar,
     Tooltip,
     Menubar,
+    Launcher,
 };
 
 struct WSAPI_WindowBackingStoreInfo {

Servers/WindowServer/WSEventLoop.cpp

@@ -211,6 +211,9 @@ bool WSEventLoop::on_receive_from_client(int client_id, const WSAPI_ClientMessag
         case WSAPI_WindowType::Menubar:
             ws_window_type = WSWindowType::Menubar;
             break;
+        case WSAPI_WindowType::Launcher:
+            ws_window_type = WSWindowType::Launcher;
+            break;
         case WSAPI_WindowType::Invalid:
         default:
             dbgprintf("Unknown WSAPI_WindowType: %d\n", message.window.type);

Servers/WindowServer/WSWindow.cpp

@@ -140,6 +140,8 @@ static WSAPI_WindowType to_api(WSWindowType ws_type)
         return WSAPI_WindowType::Tooltip;
     case WSWindowType::Menubar:
         return WSAPI_WindowType::Menubar;
+    case WSWindowType::Launcher:
+        return WSAPI_WindowType::Launcher;
     default:
         ASSERT_NOT_REACHED();
     }

Servers/WindowServer/WSWindowManager.h

@@ -277,6 +277,8 @@ IterationDecision WSWindowManager::for_each_visible_window_of_type_from_back_to_
 template<typename Callback>
 IterationDecision WSWindowManager::for_each_visible_window_from_back_to_front(Callback callback)
 {
+    if (for_each_visible_window_of_type_from_back_to_front(WSWindowType::Launcher, callback) == IterationDecision::Break)
+        return IterationDecision::Break;
     if (for_each_visible_window_of_type_from_back_to_front(WSWindowType::Normal, callback) == IterationDecision::Break)
         return IterationDecision::Break;
     if (for_each_visible_window_of_type_from_back_to_front(WSWindowType::Taskbar, callback) == IterationDecision::Break)
@@ -326,7 +328,9 @@ IterationDecision WSWindowManager::for_each_visible_window_from_front_to_back(Ca
         return IterationDecision::Break;
     if (for_each_visible_window_of_type_from_front_to_back(WSWindowType::Tooltip, callback) == IterationDecision::Break)
         return IterationDecision::Break;
-    return for_each_visible_window_of_type_from_front_to_back(WSWindowType::Normal, callback);
+    if (for_each_visible_window_of_type_from_front_to_back(WSWindowType::Normal, callback) == IterationDecision::Break)
+        return IterationDecision::Break;
+    return for_each_visible_window_of_type_from_front_to_back(WSWindowType::Launcher, callback);
 }
 
 template<typename Callback>

Servers/WindowServer/WSWindowType.h

@@ -1,5 +1,6 @@
 #pragma once
 
+// Keep this in sync with GWindowType.
 enum class WSWindowType {
     Invalid = 0,
     Normal,
@@ -8,4 +9,5 @@ enum class WSWindowType {
     Taskbar,
     Tooltip,
     Menubar,
+    Launcher,
 };