Add setOtaPolicy/getOtaPolicy API in DPMS

Allow device owners to set OTA policy for automatically accept/postpone
incoming OTA system updates. This class only provides the setting
and getting of OTA policy, the actual OTA subsystem should handle
and respect the policy stored here.

Bug: 19650524
Change-Id: I9b64949fab42097429b7da649039c13f42c10fd1
8 files changed