Add the people search value to the apps list search enum.

R=isherman@chromium.org, jar@chromium.org
BUG=None.

Review URL: https://codereview.chromium.org/121923003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@242645 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 242645