renamed HasFocus() to IsActive() to avoid confusion with FindFocus(); documented it; avoid code duplication in GTK1 version

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@29401 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/toplevel.cpp

@@ -1067,13 +1067,12 @@ bool wxTopLevelWindowGTK::SetShape(const wxRegion& region)
     return do_shape_combine_region(window, region);
 }
 
-bool wxTopLevelWindowGTK::HasFocus()
+bool wxTopLevelWindowGTK::IsActive()
 {
 #ifdef __WXGTK20__
     return GTK_WINDOW( m_widget )->has_toplevel_focus;
 #else
-    return ( wxGetTopLevelParent(FindFocus()) = this );
+    return wxTopLevelWindowBase::IsActive();
 #endif
 }
 
-// vi:sts=4:sw=4:et