Add virtual destruction file to make gcc 4.7 can compile it

BUG=None
TEST=compile passed

Change-Id: I4b4fb763aa820e7096a78087ddd6e87e900a347c
Reviewed-on: https://gerrit.chromium.org/gerrit/21667
Reviewed-by: Will Drewry <wad@chromium.org>
Commit-Ready: Yunlian Jiang <yunlian@chromium.org>
Tested-by: Yunlian Jiang <yunlian@chromium.org>
1 file changed