Remove QuicString wrapper for std::string

gfe-relnote: n/a (no functional change)
PiperOrigin-RevId: 238124961
Change-Id: I36e66a4326b4118d70effd356aef9734d2893763
diff --git a/quic/core/quic_stream.cc b/quic/core/quic_stream.cc
index 91dace4..ef621fe 100644
--- a/quic/core/quic_stream.cc
+++ b/quic/core/quic_stream.cc
@@ -4,6 +4,8 @@
 
 #include "net/third_party/quiche/src/quic/core/quic_stream.h"
 
+#include <string>
+
 #include "net/third_party/quiche/src/quic/core/quic_flow_controller.h"
 #include "net/third_party/quiche/src/quic/core/quic_session.h"
 #include "net/third_party/quiche/src/quic/core/quic_utils.h"
@@ -12,7 +14,6 @@
 #include "net/third_party/quiche/src/quic/platform/api/quic_flags.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_logging.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_str_cat.h"
-#include "net/third_party/quiche/src/quic/platform/api/quic_string.h"
 
 using spdy::SpdyPriority;