Remove the test-only X509Certificate constructor

extensions/browser/api/cast_channel/cast_socket_unittest.cc

Index: extensions/browser/api/cast_channel/cast_socket_unittest.cc
diff --git a/extensions/browser/api/cast_channel/cast_socket_unittest.cc b/extensions/browser/api/cast_channel/cast_socket_unittest.cc
index e0433b924c5ed975919257922514a0b181e1c344..6445c35d1baf6e0ff001cc8211174368fd92af7d 100644
--- a/extensions/browser/api/cast_channel/cast_socket_unittest.cc
+++ b/extensions/browser/api/cast_channel/cast_socket_unittest.cc
@@ -30,11 +30,13 @@
 #include "extensions/common/api/cast_channel/cast_channel.pb.h"
 #include "net/base/address_list.h"
 #include "net/base/net_errors.h"
+#include "net/base/test_data_directory.h"
 #include "net/log/test_net_log.h"
 #include "net/socket/socket_test_util.h"
 #include "net/socket/ssl_client_socket.h"
 #include "net/socket/tcp_client_socket.h"
 #include "net/ssl/ssl_info.h"
+#include "net/test/cert_test_util.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ -316,10 +318,10 @@ class TestCastSocket : public CastSocketImpl {
   }
 
   scoped_refptr<net::X509Certificate> ExtractPeerCert() override {
-    return extract_cert_result_ ? make_scoped_refptr<net::X509Certificate>(
-                                      new net::X509Certificate(
-                                          "", "", base::Time(), base::Time()))
-                                : nullptr;
+    return extract_cert_result_
+               ? net::ImportCertFromFile(net::GetTestCertsDirectory(),
+                                         "ok_cert.pem")
+               : nullptr;
   }
 
   bool VerifyChallengeReply() override {