sync: SyncableService support for starting sync.

Still has no actual effect as operational bits are behind the --sync-enable-deferred-startup flag.  If you pass that flag, autofill will now be permitted to kick off sync init (in fact, it will be the only thing that can kick off sync init, so you probably don't want to pass the flag yet!).

Next I'll add a fallback timer and plumb the flare to more datatypes; non Sync API types will have to call ProfileSyncService directly.

[email protected]
^ For web_data_service_factory as changes are just basic consequence of the parameter change to AutocompleteSyncableService already LGTM'd.

BUG=80194

Review URL: https://chromiumcodereview.appspot.com/14018026

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@198309 0039d316-1c4b-4281-b951-d872f2087c98
9 files changed