Add Nearby Messages API to proguard config The Physical Web feature of Chrome can take advantage of the Nearby API, so we need to keep proguard from removing it. BUG=623638 Change-Id: I6e9d736d5b36396762aec3415a56149a0137647f Reviewed-on: https://chromium-review.googlesource.com/356196 Reviewed-by: Matt Reynolds <[email protected]> Reviewed-by: Nicolas Dossou-Gbété <[email protected]> Reviewed-by: Ross McIlroy <[email protected]> Tested-by: Ross McIlroy <[email protected]>