Fix leaks introduced by CLs 27548004

CL 27548004 introduced some memory leaks in unit tests by not cleaning
up properly during shutdown. CL 33793003 fixed some of the leaks but
missed a few others. This CL fixes the remaining leaks.

BUG=287802
TEST=valgrind and heap checker show no more leaks
TBR=jyasskin@chromium.org

Review URL: https://codereview.chromium.org/35043002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@230107 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 230107