Adds mojo/shell/test/run_all_unittests.cc

R=darin@chromium.org
BUG=none
TBR=darin@chromium.org

Review URL: https://codereview.chromium.org/57993002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@232719 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 232719