Fixing valgrind problem with new multi user testing platform

BUG=-
R=oshima@chromium.org
TBR=oshima@chromium.org
TEST=local valgrind run

Review URL: https://codereview.chromium.org/38563004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@231158 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 231158