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

quic/core/quic_framer.cc

diff --git a/quic/core/quic_framer.cc b/quic/core/quic_framer.cc
index 2ffb762..22d0ecf 100644
--- a/quic/core/quic_framer.cc
+++ b/quic/core/quic_framer.cc
@@ -1368,7 +1368,7 @@
       IpAddressFamily::IP_UNSPEC) {
     // packet.client_address is non-empty.
     QuicSocketAddressCoder address_coder(packet.client_address);
-    QuicString serialized_address = address_coder.Encode();
+    std::string serialized_address = address_coder.Encode();
     if (serialized_address.empty()) {
       return nullptr;
     }
@@ -1994,7 +1994,7 @@
   QuicStringPiece endpoint_id;
   if (perspective_ == Perspective::IS_CLIENT &&
       reset->GetStringPiece(kEPID, &endpoint_id)) {
-    packet.endpoint_id = QuicString(endpoint_id);
+    packet.endpoint_id = std::string(endpoint_id);
     packet.endpoint_id += '\0';
   }
 
@@ -3724,7 +3724,7 @@
     set_detailed_error("Unable to read connection close error details.");
     return false;
   }
-  frame->error_details = QuicString(error_details);
+  frame->error_details = std::string(error_details);
 
   return true;
 }
@@ -3755,7 +3755,7 @@
     set_detailed_error("Unable to read goaway reason.");
     return false;
   }
-  frame->reason_phrase = QuicString(reason_phrase);
+  frame->reason_phrase = std::string(reason_phrase);
 
   return true;
 }
@@ -4511,7 +4511,7 @@
     set_detailed_error("Unable to read new token data.");
     return false;
   }
-  frame->token = QuicString(data);
+  frame->token = std::string(data);
   return true;
 }
 
@@ -5225,7 +5225,7 @@
     set_detailed_error("Unable to read connection close error details.");
     return false;
   }
-  frame->error_details = QuicString(phrase);
+  frame->error_details = std::string(phrase);
 
   return true;
 }
@@ -5250,7 +5250,7 @@
     set_detailed_error("Unable to read application close error details.");
     return false;
   }
-  frame->error_details = QuicString(phrase);
+  frame->error_details = std::string(phrase);
 
   return true;
 }