Avoid creating and immediately destroying a wxGraphicsContext for most uses of wxGCDC.

This also causes the dummy "measuring context" to be properly initialized with a default font


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72019 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/dcgraph.h

@@ -68,9 +68,6 @@ public:
 
     virtual ~wxGCDCImpl();
 
-    void Init();
-
-
     // implement base class pure virtuals
     // ----------------------------------
 
@@ -213,6 +210,9 @@ protected:
 
     wxGraphicsContext* m_graphicContext;
 
+private:
+    void Init(wxGraphicsContext*);
+
     DECLARE_CLASS(wxGCDCImpl)
     wxDECLARE_NO_COPY_CLASS(wxGCDCImpl);
 };