Enable passing cast channel certificate authority keys.

extensions/browser/api/cast_channel/cast_auth_util.h

Index: extensions/browser/api/cast_channel/cast_auth_util.h
diff --git a/extensions/browser/api/cast_channel/cast_auth_util.h b/extensions/browser/api/cast_channel/cast_auth_util.h
index 560f698d2b57430d7071dcae8d5b218426a094d9..ea182150135a749c7a5711e3b368d342f0a97daf 100644
--- a/extensions/browser/api/cast_channel/cast_auth_util.h
+++ b/extensions/browser/api/cast_channel/cast_auth_util.h
@@ -58,6 +58,10 @@ struct AuthResult {
 AuthResult AuthenticateChallengeReply(const CastMessage& challenge_reply,
                                       const std::string& peer_cert);
 
+// Sets trusted certificate authorities.
+bool SetTrustedCertificateAuthorities(const std::string& signature,
+                                      const std::string& keys);
+
 }  // namespace cast_channel
 }  // namespace core_api
 }  // namespace extensions