Specify device type for authcode requests to DMServer.

Defines device type enum for the robot auth code request.
This is required for the migration to CreateOAuthToken call to LSO backend.

BUG=693702

Review-Url: https://codereview.chromium.org/2714163003
Cr-Original-Commit-Position: refs/heads/master@{#453583}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 35275d0100464cc6f401e8307ae9dc2dc32d6cd8
1 file changed