network_3GActivateCdma: Several improvements.

1. Retry activation and connection if they fail, and tally failed attempts.
2. Watch activation state instead of service state to see when activation
   completes.
3. Pull out all of the keys that we watch (e.g. Cellular.ActivationState) as
   constants to avoid typos.
4. Activate through service (flimflam), not modem (modemmanager).  This means
   we see activation failures!

BUG=chromium-os:23470
TEST=is one, passes

Change-Id: I7f68855ae84584dc3ce165ba2d78dc811e4796c9
Reviewed-on: https://gerrit.chromium.org/gerrit/12705
Reviewed-by: Jason Glasgow <jglasgow@chromium.org>
Commit-Ready: ttuttle <ttuttle@chromium.org>
Tested-by: ttuttle <ttuttle@chromium.org>
1 file changed