Avoids the "re-encode HPACK as SPDY3" step.

net/quic/quic_spdy_stream.h

 // Copyright 2013 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.
 //
 // The base class for streams which deliver data to/from an application.
 // In each direction, the data on such a stream first contains compressed
 // headers then body data.
 
 #ifndef NET_QUIC_QUIC_SPDY_STREAM_H_
 #define NET_QUIC_QUIC_SPDY_STREAM_H_
@@ skipping 122 matching lines @@
   // headers stream. Trailers will always have the FIN set.
   virtual size_t WriteTrailers(const SpdyHeaderBlock& trailer_block,
                                QuicAckListenerInterface* ack_notifier_delegate);
 
   // Marks |bytes_consumed| of the headers data as consumed.
   void MarkHeadersConsumed(size_t bytes_consumed);
 
   // Marks |bytes_consumed| of the trailers data as consumed.
   void MarkTrailersConsumed(size_t bytes_consumed);
 
+  // Marks the trailers as consumed.
+  void MarkTrailersDelivered();
+
   // Clears |header_list_|.
   void ConsumeHeaderList();
 
   // This block of functions wraps the sequencer's functions of the same
   // name.  These methods return uncompressed data until that has
   // been fully processed.  Then they simply delegate to the sequencer.
   virtual size_t Readv(const struct iovec* iov, size_t iov_len);
   virtual int GetReadableRegions(iovec* iov, size_t iov_len) const;
   void MarkConsumed(size_t num_bytes);
 
@@ skipping 73 matching lines @@
   SpdyPriority priority_;
   // Contains a copy of the decompressed headers until they are consumed
   // via ProcessData or Readv.
   std::string decompressed_headers_;
   // Contains a copy of the decompressed header (name, value) pairs until they
   // are consumed via Readv.
   QuicHeaderList header_list_;
 
   // True if the trailers have been completely decompressed.
   bool trailers_decompressed_;
+  // True if the trailers have been consumed.
+  bool trailers_delivered_;
   // Contains a copy of the decompressed trailers until they are consumed
   // via ProcessData or Readv.
   std::string decompressed_trailers_;
   // The parsed trailers received from the peer.
   SpdyHeaderBlock received_trailers_;
 
   bool avoid_empty_nonfin_writes_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicSpdyStream);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_SPDY_STREAM_H_