Modify service_connector_unitttest to use Service<>

BUG=None
TEST=existing
R=darin@chromium.org, darin

Review URL: https://codereview.chromium.org/135683007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@248596 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 248596