Add "packet_capture" as a dev command in crosh

Add a dev-mode-only "packet_capture" command that uses debugd
to run a device-based or monitored packet capture.

CQ-DEPEND=CL:50010
BUG=chromium:218380
TEST=manual tests on a daisy with a USB WiFi dongle.

Change-Id: I057a27034a923310e7b8665d66b224af08958273
Reviewed-on: https://gerrit.chromium.org/gerrit/50014
Reviewed-by: Elly Jones <ellyjones@chromium.org>
Commit-Queue: Paul Stewart <pstew@chromium.org>
Tested-by: Paul Stewart <pstew@chromium.org>
1 file changed