debugd: Provide RunModemCommand API to run modem AT commands.

The API is required because communication with the serial interface
requires root privileges. The API will be used to implement the
corresponding crosh modem commands through DBus.

BUG=chrome-os-partner:17809
TEST=unit tests; tested on device along with relevant 'modem' script CL by
issuing relevant modem commands

Change-Id: I253f55a9bd1a2bdaca43ff6b40b68df07ccbd96c
Reviewed-on: https://gerrit.chromium.org/gerrit/44399
Tested-by: Darin Petkov <petkov@chromium.org>
Reviewed-by: Elly Jones <ellyjones@chromium.org>
Reviewed-by: Jorge Lucangeli Obes <jorgelo@chromium.org>
Commit-Queue: Darin Petkov <petkov@chromium.org>
8 files changed
tree: f848cf2b6e158174264a99435430c7cf0842681e
  1. doc/
  2. share/
  3. src/
  4. .gitignore
  5. Makefile
  6. OWNERS
  7. README