Replace QuicString with std::string, pass 1

This replaces QuicString with std::string in all of the "QUIC proper".  I will
delete QuicString once all code using it is gone.

gfe-relnote: n/a (no functional change)
PiperOrigin-RevId: 237872023
Change-Id: I82de62c9855516b15039734d05155917e68ff4ee
diff --git a/quic/core/frames/quic_new_token_frame.cc b/quic/core/frames/quic_new_token_frame.cc
index c2f4e74..6e36866 100644
--- a/quic/core/frames/quic_new_token_frame.cc
+++ b/quic/core/frames/quic_new_token_frame.cc
@@ -12,7 +12,7 @@
     : control_frame_id(kInvalidControlFrameId) {}
 
 QuicNewTokenFrame::QuicNewTokenFrame(QuicControlFrameId control_frame_id,
-                                     QuicString token)
+                                     std::string token)
     : control_frame_id(control_frame_id), token(token) {}
 
 std::ostream& operator<<(std::ostream& os, const QuicNewTokenFrame& s) {