Make QuicSpdyStream::WriteTrailers virtual for tests. No behavior change.

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 81 matching lines @@
   void OnStreamReset(const QuicRstStreamFrame& frame) override;
 
   // Writes the headers contained in |header_block| to the dedicated
   // headers stream.
   virtual size_t WriteHeaders(const SpdyHeaderBlock& header_block,
                               bool fin,
                               QuicAckListenerInterface* ack_notifier_delegate);
 
   // Writes the trailers contained in |trailer_block| to the dedicated
   // headers stream. Trailers will always have the FIN set.
-  size_t WriteTrailers(SpdyHeaderBlock trailer_block,
-                       QuicAckListenerInterface* ack_notifier_delegate);
+  virtual size_t WriteTrailers(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);
 
   // 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.
@@ skipping 58 matching lines @@
   // Contains a copy of the decompressed trailers until they are consumed
   // via ProcessData or Readv.
   std::string decompressed_trailers_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicSpdyStream);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_SPDY_STREAM_H_