Enable passing cast channel certificate authority keys.

extensions/common/api/cast_channel/authority_keys.proto

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 syntax = "proto2";
 
 option optimize_for = LITE_RUNTIME;
 
-package leveldb_proto;
+package extensions.core_api.cast_channel.proto;
 
-// A proto to test leveldb_proto::ProtoDatabaseImpl.
-//
-// Next tag: 3
-message TestProto {
-  // Arbitary id.
-  optional string id = 1;
-
-  // Arbitrary data.
-  optional string data = 2;
+message AuthorityKeys {
+  message Key {
+    required bytes fingerprint = 1;
+    required bytes public_key = 2;
+  }
+  repeated Key keys = 1;
 }