Refactor X509Certificate caching to cache the OS handle, rather than the X509Certificate

net/socket/ssl_client_socket_mac.cc

Index: net/socket/ssl_client_socket_mac.cc
diff --git a/net/socket/ssl_client_socket_mac.cc b/net/socket/ssl_client_socket_mac.cc
index fa283ab08cdffcac7614c673d0d563d06ec6d314..dbff6a15373f9c450f3e8f9f01a86e1ce37ff3f1 100644
--- a/net/socket/ssl_client_socket_mac.cc
+++ b/net/socket/ssl_client_socket_mac.cc
@@ -460,8 +460,8 @@ X509Certificate* GetServerCert(SSLContextRef ssl_context) {
 
   SecCertificateRef server_cert = static_cast<SecCertificateRef>(
       const_cast<void*>(CFArrayGetValueAtIndex(certs, 0)));
-  return X509Certificate::CreateFromHandle(
-      server_cert, X509Certificate::SOURCE_FROM_NETWORK, intermediate_ca_certs);
+  return X509Certificate::CreateFromHandle(server_cert,
+                                           intermediate_ca_certs);
 }
 
 // Dynamically look up a pointer to a function exported by a bundle.