cellular: pseudomodem: Support CDMA activation.

Implemented fake 'OTA automatic activation' mechanism.

BUG=chromium:219160
TEST=1. Initialize pseudo modem manager as 'not-activated' (use the -n flag).
        Not providing the '-n' flag to pseudomodem.py should initialize
        the modem as 'activated'. Note that the -n flag currently only
        works if "-f CDMA" is also passed. Verify that the CDMA
        ActivationState property is set to 'not-activated' when -n is
        present
     2. Activate the modem using "mmcli -m 0 --cdma-activate=0000".
        Use mmcli to verify that the CDMA ActivationState property is set to
        'activating'.
     3. Wait 5 seconds. The modem should reset (i.e. runnin mmcli -m 0 should
        return an error. The modem should be available at mmcli -m 1.)
        The CDMA ActivationState property should be set to 'activated'.

Change-Id: I0091ea5f6ab355914d27b1a402458bb9cbc130d0
Reviewed-on: https://gerrit.chromium.org/gerrit/50416
Commit-Queue: Arman Uguray <armansito@chromium.org>
Reviewed-by: Arman Uguray <armansito@chromium.org>
Tested-by: Arman Uguray <armansito@chromium.org>
Reviewed-by: Ben Chan <benchan@chromium.org>
5 files changed