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/quic_stream_sequencer_buffer.cc b/quic/core/quic_stream_sequencer_buffer.cc
index 485c9dc..75000bd 100644
--- a/quic/core/quic_stream_sequencer_buffer.cc
+++ b/quic/core/quic_stream_sequencer_buffer.cc
@@ -71,7 +71,7 @@
     QuicStreamOffset starting_offset,
     QuicStringPiece data,
     size_t* const bytes_buffered,
-    QuicString* error_details) {
+    std::string* error_details) {
   *bytes_buffered = 0;
   size_t size = data.size();
   if (size == 0) {
@@ -158,7 +158,7 @@
 bool QuicStreamSequencerBuffer::CopyStreamData(QuicStreamOffset offset,
                                                QuicStringPiece data,
                                                size_t* bytes_copy,
-                                               QuicString* error_details) {
+                                               std::string* error_details) {
   *bytes_copy = 0;
   size_t source_remaining = data.size();
   if (source_remaining == 0) {
@@ -236,7 +236,7 @@
 QuicErrorCode QuicStreamSequencerBuffer::Readv(const iovec* dest_iov,
                                                size_t dest_count,
                                                size_t* bytes_read,
-                                               QuicString* error_details) {
+                                               std::string* error_details) {
   *bytes_read = 0;
   for (size_t i = 0; i < dest_count && ReadableBytes() > 0; ++i) {
     char* dest = reinterpret_cast<char*>(dest_iov[i].iov_base);
@@ -500,12 +500,12 @@
   }
 }
 
-QuicString QuicStreamSequencerBuffer::GapsDebugString() {
+std::string QuicStreamSequencerBuffer::GapsDebugString() {
   // TODO(vasilvv): this should return the complement of |bytes_received_|.
   return bytes_received_.ToString();
 }
 
-QuicString QuicStreamSequencerBuffer::ReceivedFramesDebugString() {
+std::string QuicStreamSequencerBuffer::ReceivedFramesDebugString() {
   return bytes_received_.ToString();
 }