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/test_tools/simulator/traffic_policer.cc b/quic/test_tools/simulator/traffic_policer.cc
index e416a7d..fa0bcfb 100644
--- a/quic/test_tools/simulator/traffic_policer.cc
+++ b/quic/test_tools/simulator/traffic_policer.cc
@@ -10,7 +10,7 @@
 namespace simulator {
 
 TrafficPolicer::TrafficPolicer(Simulator* simulator,
-                               QuicString name,
+                               std::string name,
                                QuicByteCount initial_bucket_size,
                                QuicByteCount max_bucket_size,
                                QuicBandwidth target_bandwidth,