[GCM] Unrevert initial GCM patch

Includes build fix for static libraries and ensure that gcm_unit_tests
is run on relevant builders.

Original codereview: https://codereview.chromium.org/23684017/

BUG=284553
TBR=darin@chromium.org

Review URL: https://codereview.chromium.org/32093003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@229982 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 229982