moved HasTransparentBackground() from wxUniv to common wxWindow

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@31272 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/univ/window.h

@@ -144,11 +144,6 @@ public:
     // controls only
     virtual bool IsCanvasWindow() const { return false; }
 
-    // returns true if the control has "transparent" areas such
-    // as a wxStaticText and wxCheckBox and the background should
-    // be adapted from a parent window
-    virtual bool HasTransparentBackground() { return false; }
-
     // return true if this control can be highlighted when the mouse is over
     // it (the theme decides itself whether it is really highlighted or not)
     virtual bool CanBeHighlighted() const { return false; }