Merge "Definition of device_role_t." am: e0bb02686a am: e2430e85c6

Original change: https://android-review.googlesource.com/c/platform/system/media/+/1534350

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I290755d31ca7c34d0cc74afbfd5108eb88069a3e