Command-line option to upgrade host config.

This adds a command-line option to the host binary. If present, the host
will test and maybe upgrade the config with a new refresh token. It will
then exit with 0 if successful (or if no action was taken). On failure,
it will retry fetching a new token, up to some maximum number of
attempts. If unsuccessful, it exits with a non-zero exit-code.

The config file is marked as updated, so that future invocations will
not attempt token-exchange (saving some queries over the network).

Bug: 954427
Change-Id: I4c95549baa5865699e14ef053fff895b9160377b
Commit-Queue: Lambros Lambrou <>
Reviewed-by: Joe Downing <>
Cr-Commit-Position: refs/heads/master@{#663326}
8 files changed