Only account for WM frame extents in tlw size if WM supports _NET_FRAME_EXTENTS. Extents cache no longer needed.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@50467 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/toplevel.h

@@ -94,6 +94,8 @@ public:
 
     GtkWidget    *m_mainWidget;
 
+    bool m_deferShow;
+
     bool          m_fsIsShowing;         /* full screen */
     int           m_fsSaveGdkFunc, m_fsSaveGdkDecor;
     wxRect        m_fsSaveFrame;
@@ -112,9 +114,6 @@ public:
     // return the size of the window without WM decorations
     void GTKDoGetSize(int *width, int *height) const;
 
-    // whether frame extents are accurate
-    virtual bool IsDecorCacheable() const;
-
 protected:
     // give hints to the Window Manager for how the size
     // of the TLW can be changed by dragging