Remove using namespace in net/quic/quic_stream_sequencer.h

net/quic/quic_headers_stream.cc

Index: net/quic/quic_headers_stream.cc
diff --git a/net/quic/quic_headers_stream.cc b/net/quic/quic_headers_stream.cc
index 10a02a7866b5b21f84f857dbae59f8079e3cb092..e6b728b6b68cecf9c02c70ca8fb38d6d4e9ef715 100644
--- a/net/quic/quic_headers_stream.cc
+++ b/net/quic/quic_headers_stream.cc
@@ -159,7 +159,7 @@ class QuicHeadersStream::SpdyFramerVisitor
   }
 
  private:
-  void CloseConnection(const string& details) {
+  void CloseConnection(const std::string& details) {
     if (stream_->IsConnected()) {
       stream_->CloseConnectionWithDetails(
           QUIC_INVALID_HEADERS_STREAM_DATA, details);