Fixing menory leak in unit test

TBR=oshima@chromium.org
BUG=-
TEST=unit test

Review URL: https://codereview.chromium.org/24281004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224615 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 224615