This commit adds macros for declaring scoped native callbacks which are
in namespace or for example defined as static class member variables.
The existing macros don't allow this as they use QtJniMethods namespace
and the introduced callbacks' namespaces are not enclosed in that
namespace, yielding a compilation error.
Pick-to: 6.4
Change-Id: I754560bea7e9a1b57c2661d1ee7236e78db39ba1
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
c5caab1f15