Upgrade WX to r74856, mainly to support @2x.

Externals/wxWidgets3/include/wx/msw/treectrl.h

@@ -4,7 +4,6 @@
 // Author:      Julian Smart
 // Modified by: Vadim Zeitlin to be less MSW-specific on 10/10/98
 // Created:     01/02/97
-// RCS-ID:      $Id: treectrl.h 64532 2010-06-09 13:55:48Z FM $
 // Copyright:   (c) Julian Smart
 // Licence:     wxWindows licence
 /////////////////////////////////////////////////////////////////////////////
@@ -212,6 +211,14 @@ public:
     virtual bool CanApplyThemeBorder() const { return false; }
 
 protected:
+    // Implement "update locking" in a custom way for this control.
+    virtual void DoFreeze();
+    virtual void DoThaw();
+
+    virtual void DoSetSize(int x, int y,
+                           int width, int height,
+                           int sizeFlags = wxSIZE_AUTO);
+
     // SetImageList helper
     void SetAnyImageList(wxImageList *imageList, int which);
 
@@ -332,6 +339,9 @@ private:
     // whether we need to deselect other items on mouse up
     bool m_mouseUpDeselect;
 
+    // The size to restore the control to when it is thawed, see DoThaw().
+    wxSize m_thawnSize;
+
     friend class wxTreeItemIndirectData;
     friend class wxTreeSortHelper;