Fix Ok/IsOk() mess in wxGDIObject-derived classes; also added

wxGDIObject::Create/CloneGDIRefData() and implemented them for (almost) all
ports


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@50727 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/mgl/bitmap.cpp

@@ -60,6 +60,8 @@ public:
     wxBitmapRefData();
     virtual ~wxBitmapRefData();
 
+    virtual bool IsOk() const { return m_bitmap != NULL; }
+
     int             m_width;
     int             m_height;
     int             m_bpp;
@@ -267,11 +269,6 @@ wxBitmap::wxBitmap(const char bits[], int width, int height, int depth)
     delete bdc;
 }
 
-bool wxBitmap::IsOk() const
-{
-    return (m_refData != NULL && M_BMPDATA->m_bitmap != NULL);
-}
-
 int wxBitmap::GetHeight() const
 {
     wxCHECK_MSG( Ok(), -1, wxT("invalid bitmap") );