Merge "Revise the comment on DUMMY_REQUEST_ID" into rvc-dev am: cea7defc

    private static final String TAG = "MR2ServiceImpl";

    private static final boolean DEBUG = Log.isLoggable(TAG, Log.DEBUG);

    /**

     * TODO: Change this with the real request ID from MediaRouter2 when

     * MediaRouter2 needs to get notified for the failures.

     */

    // TODO: (In Android S or later) if we add callback methods for generic failures

    //       in MediaRouter2, remove this constant and replace the usages with the real request IDs.

    private static final long DUMMY_REQUEST_ID = -1;

    private final Context mContext;