Delete unused field from AndroidVideoTrackSource

BUG=None

Review-Url: https://codereview.webrtc.org/2974713002
Cr-Commit-Position: refs/heads/master@{#19117}
diff --git a/AUTHORS b/AUTHORS
index 8c7e4d7..ed702b6 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -54,6 +54,7 @@
 Victor Costan <costan@gmail.com>
 Xiaohong Xu <freemine@yeah.net>
 Hans Knoechel <hans@hans-knoechel.de>
+Korniltsev Anatoly <korniltsev.anatoly@gmail.com>
 
 &yet LLC <*@andyet.com>
 Agora IO <*@agora.io>