Remove QuicString wrapper for std::string

gfe-relnote: n/a (no functional change)
PiperOrigin-RevId: 238124961
Change-Id: I36e66a4326b4118d70effd356aef9734d2893763

quic/quartc/quartc_crypto_helpers.h

diff --git a/quic/quartc/quartc_crypto_helpers.h b/quic/quartc/quartc_crypto_helpers.h
index c53a58e..2dba7ac 100644
--- a/quic/quartc/quartc_crypto_helpers.h
+++ b/quic/quartc/quartc_crypto_helpers.h
@@ -5,6 +5,8 @@
 #ifndef QUICHE_QUIC_QUARTC_QUARTC_CRYPTO_HELPERS_H_
 #define QUICHE_QUIC_QUARTC_QUARTC_CRYPTO_HELPERS_H_
 
+#include <string>
+
 #include "net/third_party/quiche/src/quic/core/crypto/crypto_handshake_message.h"
 #include "net/third_party/quiche/src/quic/core/crypto/proof_source.h"
 #include "net/third_party/quiche/src/quic/core/crypto/proof_verifier.h"
@@ -15,7 +17,6 @@
 #include "net/third_party/quiche/src/quic/core/quic_versions.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_reference_counted.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_socket_address.h"
-#include "net/third_party/quiche/src/quic/platform/api/quic_string.h"
 #include "net/third_party/quiche/src/quic/platform/api/quic_string_piece.h"
 
 namespace quic {