In QUIC, send data is copied to streams rather than frames. Protected by FLAGS_quic_reloadable_flag…

net/quic/core/frames/quic_stream_frame.h

 // Copyright (c) 2016 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.
 
 #ifndef NET_QUIC_CORE_FRAMES_QUIC_STREAM_FRAME_H_
 #define NET_QUIC_CORE_FRAMES_QUIC_STREAM_FRAME_H_
 
 #include <memory>
 #include <ostream>
 
@@ skipping 32 matching lines @@
   QuicStreamFrame();
   QuicStreamFrame(QuicStreamId stream_id,
                   bool fin,
                   QuicStreamOffset offset,
                   QuicStringPiece data);
   QuicStreamFrame(QuicStreamId stream_id,
                   bool fin,
                   QuicStreamOffset offset,
                   QuicPacketLength data_length,
                   UniqueStreamBuffer buffer);
+  QuicStreamFrame(QuicStreamId stream_id,
+                  bool fin,
+                  QuicStreamOffset offset,
+                  QuicPacketLength data_length);
   ~QuicStreamFrame();
 
   friend QUIC_EXPORT_PRIVATE std::ostream& operator<<(std::ostream& os,
                                                       const QuicStreamFrame& s);
 
   QuicStreamId stream_id;
   bool fin;
   QuicPacketLength data_length;
   const char* data_buffer;
   QuicStreamOffset offset;  // Location of this data in the stream.
+  // TODO(fayang): When deprecating
+  // FLAGS_quic_reloadable_flag_quic_stream_owns_data: (1) Remove buffer from
+  // QuicStreamFrame; (2) remove the constructor uses UniqueStreamBuffer and (3)
+  // Move definition of UniqueStreamBuffer to QuicStreamSendBuffer.
   // nullptr when the QuicStreamFrame is received, and non-null when sent.
   UniqueStreamBuffer buffer;
 
  private:
   QuicStreamFrame(QuicStreamId stream_id,
                   bool fin,
                   QuicStreamOffset offset,
                   const char* data_buffer,
                   QuicPacketLength data_length,
                   UniqueStreamBuffer buffer);
 
   DISALLOW_COPY_AND_ASSIGN(QuicStreamFrame);
 };
 static_assert(sizeof(QuicStreamFrame) <= 64,
               "Keep the QuicStreamFrame size to a cacheline.");
 
 }  // namespace net
 
 #endif  // NET_QUIC_CORE_FRAMES_QUIC_STREAM_FRAME_H_