[Merge to 2881 for release cherry-picking] Re-enable the QUIC v33 hacks. protected by FLAGS_quic_re…

net/quic/core/quic_framer.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/core/quic_framer.h"
 
 #include <cstdint>
 #include <memory>
 #include <vector>
 
@@ skipping 705 matching lines @@
   switch (header.public_header.connection_id_length) {
     case PACKET_0BYTE_CONNECTION_ID:
       if (!writer->WriteUInt8(public_flags |
                               PACKET_PUBLIC_FLAGS_0BYTE_CONNECTION_ID)) {
         return false;
       }
       break;
     case PACKET_8BYTE_CONNECTION_ID:
       if (quic_version_ > QUIC_VERSION_32) {
         public_flags |= PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID;
+        if (!FLAGS_quic_remove_v33_hacks2 &&
+            perspective_ == Perspective::IS_CLIENT) {
+          public_flags |= PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID_OLD;
+        }
+
       } else {
         public_flags |= PACKET_PUBLIC_FLAGS_8BYTE_CONNECTION_ID_OLD;
       }
       if (!writer->WriteUInt8(public_flags) ||
           !writer->WriteUInt64(header.public_header.connection_id)) {
         return false;
       }
       break;
   }
   last_serialized_connection_id_ = header.public_header.connection_id;
@@ skipping 1900 matching lines @@
 
 bool QuicFramer::RaiseError(QuicErrorCode error) {
   DVLOG(1) << "Error: " << QuicUtils::ErrorToString(error)
            << " detail: " << detailed_error_;
   set_error(error);
   visitor_->OnError(this);
   return false;
 }
 
 }  // namespace net