Enable passing cast channel certificate authority keys.

extensions/common/api/cast_channel/authority_keys.proto

Index: extensions/common/api/cast_channel/authority_keys.proto
diff --git a/components/leveldb_proto/testing/proto/test.proto b/extensions/common/api/cast_channel/authority_keys.proto
similarity index 52%
copy from components/leveldb_proto/testing/proto/test.proto
copy to extensions/common/api/cast_channel/authority_keys.proto
index 84981051657158a9eb44ddcd5cd8b63556a1e97c..aba7488180b8a3b3357a902aa4e104f277887068 100644
--- a/components/leveldb_proto/testing/proto/test.proto
+++ b/extensions/common/api/cast_channel/authority_keys.proto
@@ -6,15 +6,12 @@ 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;
 }