Remove using namespace in net/quic/quic_stream_sequencer.h

net/tools/quic/quic_server_session_test.cc

Index: net/tools/quic/quic_server_session_test.cc
diff --git a/net/tools/quic/quic_server_session_test.cc b/net/tools/quic/quic_server_session_test.cc
index 4705c05aa0145d34e00f2e222173d420759bfae9..c4c8f3ed07bcf773b71ff51cff9211a3ae9ca31b 100644
--- a/net/tools/quic/quic_server_session_test.cc
+++ b/net/tools/quic/quic_server_session_test.cc
@@ -4,6 +4,8 @@
 
 #include "net/tools/quic/quic_server_session.h"
 
+#include <string>
+
 #include "net/quic/crypto/cached_network_parameters.h"
 #include "net/quic/crypto/quic_crypto_server_config.h"
 #include "net/quic/crypto/quic_random.h"
@@ -37,6 +39,7 @@ using net::test::kClientDataStreamId1;
 using net::test::kClientDataStreamId2;
 using net::test::kClientDataStreamId3;
 using net::test::kClientDataStreamId4;
+using std::string;
 using testing::StrictMock;
 using testing::_;