Deprecate not working wxSplitterWindow::SetSashSize().

Setting sash size to non default value didn't work correctly and didn't make
much sense anyhow as the sash appearance is platform-dependent and current
code for drawing it doesn't work for arbitrary sizes.

Simply remove the possibility to set the sash size.

Closes #12412.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66232 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/generic/splitter.h

@@ -133,9 +133,6 @@ public:
     // Is the window split?
     bool IsSplit() const { return (m_windowTwo != NULL); }
 
-    // Sets the sash size
-    void SetSashSize(int width) { m_sashSize = width; }
-
     // Sets the border size
     void SetBorderSize(int WXUNUSED(width)) { }
 
@@ -221,6 +218,10 @@ public:
     virtual bool MacClipGrandChildren() const { return true ; }
 #endif
 
+    // Sets the sash size: this doesn't do anything and shouldn't be used at
+    // all any more.
+    wxDEPRECATED_INLINE( void SetSashSize(int WXUNUSED(width)), return; )
+
 protected:
     // event handlers
 #if defined(__WXMSW__) || defined(__WXMAC__)
@@ -282,7 +283,6 @@ protected:
     int         m_oldY;         // current tracker position if not live mode
     int         m_sashPosition; // Number of pixels from left or top
     double      m_sashGravity;
-    int         m_sashSize;
     wxSize      m_lastSize;
     int         m_requestedSashPosition;
     int         m_sashPositionCurrent; // while dragging