net: allow SSL secrets to be exported sooner.

net/socket/ssl_client_socket_nss.cc

Index: net/socket/ssl_client_socket_nss.cc
diff --git a/net/socket/ssl_client_socket_nss.cc b/net/socket/ssl_client_socket_nss.cc
index eddac5c99ad51819a1a32a2185dba6b722945468..42acb81024e3cc1e3d32fb13062fa37697535427 100644
--- a/net/socket/ssl_client_socket_nss.cc
+++ b/net/socket/ssl_client_socket_nss.cc
@@ -529,9 +529,8 @@ int SSLClientSocketNSS::ExportKeyingMaterial(const base::StringPiece& label,
                                              unsigned int outlen) {
   if (!IsConnected())
     return ERR_SOCKET_NOT_CONNECTED;
-  std::string label_string(label.data(), label.length());
   SECStatus result = SSL_ExportKeyingMaterial(
-      nss_fd_, label_string.c_str(),
+      nss_fd_, label.data(), label.size(),
       reinterpret_cast<const unsigned char*>(context.data()),
       context.length(), out, outlen);
   if (result != SECSuccess) {