Reuse window classes

This gets rid of some unnecessary complexity.

src/wine-host/editor.h

@@ -55,21 +55,6 @@ struct Size {
     uint16_t height;
 };
 
-/**
- * A basic RAII wrapper around the Win32 window class system, for use in the
- * Editor class below.
- */
-class WindowClass {
-   public:
-    explicit WindowClass(const std::string& name);
-    ~WindowClass();
-
-    /**
-     * The Win32 window class registered for the windows window.
-     */
-    const ATOM atom;
-};
-
 /**
  * A wrapper around the win32 windowing API to create and destroy editor
  * windows. We can embed this window into the window provided by the host, and a
@@ -220,11 +205,6 @@ class Editor {
      */
     const Size client_area;
 
-    /**
-     * The Win32 window class registered for the windows window.
-     */
-    const WindowClass window_class;
-
     // FIXME: This emits `-Wignored-attributes` as of Wine 5.22
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wignored-attributes"