Merge commit 'a5188a09bd20c376b4f0645b0df4c52f8e114e21' * commit 'a5188a09bd20c376b4f0645b0df4c52f8e114e21': Add virtual destructor.
Merge commit 'a5188a09bd20c376b4f0645b0df4c52f8e114e21' * commit 'a5188a09bd20c376b4f0645b0df4c52f8e114e21': Add virtual destructor.