LibCore: Introduce a C_OBJECT macro.

This macro goes at the top of every CObject-derived class like so:

class SomeClass : public CObject {
    C_OBJECT(SomeClass)
public:
    ...

At the moment, all it does is create an override for the class_name() getter
but in the future this will be used to automatically insert member functions
into these classes.

Servers/WindowServer/WSCompositor.h

@@ -19,6 +19,7 @@ enum class WallpaperMode {
 };
 
 class WSCompositor final : public CObject {
+    C_OBJECT(WSCompositor)
 public:
     static WSCompositor& the();
 
@@ -35,8 +36,6 @@ public:
     Rect current_cursor_rect() const;
 
 private:
-    virtual const char* class_name() const override { return "WSCompositor"; }
-
     WSCompositor();
     void flip_buffers();
     void flush(const Rect&);

Servers/WindowServer/WSMenu.h

@@ -14,6 +14,7 @@ class WSWindow;
 class Font;
 
 class WSMenu final : public CObject {
+    C_OBJECT(WSMenu)
 public:
     WSMenu(WSClientConnection*, int menu_id, const String& name);
     virtual ~WSMenu() override;

Servers/WindowServer/WSMenuManager.h

@@ -5,6 +5,7 @@
 #include <WindowServer/WSWindow.h>
 
 class WSMenuManager final : public CObject {
+    C_OBJECT(WSMenuManager)
 public:
     WSMenuManager();
     virtual ~WSMenuManager() override;
@@ -13,7 +14,6 @@ public:
     void refresh();
 
     virtual void event(CEvent&) override;
-    virtual const char* class_name() const override { return "WSMenuManager"; }
 
 private:
     WSWindow& window() { return *m_window; }

Servers/WindowServer/WSWindow.h

@@ -16,6 +16,7 @@ class WSMouseEvent;
 
 class WSWindow final : public CObject
     , public InlineLinkedListNode<WSWindow> {
+    C_OBJECT(WSWindow)
 public:
     WSWindow(WSClientConnection&, WSWindowType, int window_id, bool modal, bool resizable, bool fullscreen);
     WSWindow(CObject&, WSWindowType);

Servers/WindowServer/WSWindowManager.h

@@ -42,6 +42,8 @@ enum class ResizeDirection {
 };
 
 class WSWindowManager : public CObject {
+    C_OBJECT(WSWindowManager)
+
     friend class WSCompositor;
     friend class WSWindowFrame;
     friend class WSWindowSwitcher;

Servers/WindowServer/WSWindowSwitcher.h

@@ -10,6 +10,7 @@ class WSKeyEvent;
 class WSWindow;
 
 class WSWindowSwitcher : public CObject {
+    C_OBJECT(WSWindowSwitcher)
 public:
     static WSWindowSwitcher& the();