sync: take two for:

Added classes to enable session sync functionality.

TEST=ProfileSyncServiceSessionTest
BUG=30519
Original patch by : jerrica@chromium.org
Original review http://codereview.chromium.org/3168009

Review URL: http://codereview.chromium.org/3133022

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@56462 0039d316-1c4b-4281-b951-d872f2087c98
46 files changed