Avoid SpdyHeaderBlock copy in SpdyStream::OnPushPromiseHeadersReceived().

net/spdy/buffered_spdy_framer.h

 // 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.
 
 #ifndef NET_SPDY_BUFFERED_SPDY_FRAMER_H_
 #define NET_SPDY_BUFFERED_SPDY_FRAMER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 21 matching lines @@
   virtual void OnStreamError(SpdyStreamId stream_id,
                              const std::string& description) = 0;
 
   // Called after all the header data for HEADERS control frame is received.
   virtual void OnHeaders(SpdyStreamId stream_id,
                          bool has_priority,
                          int weight,
                          SpdyStreamId parent_stream_id,
                          bool exclusive,
                          bool fin,
-                         const SpdyHeaderBlock& headers) = 0;
+                         SpdyHeaderBlock headers) = 0;
 
   // Called when a data frame header is received.
   virtual void OnDataFrameHeader(SpdyStreamId stream_id,
                                  size_t length,
                                  bool fin) = 0;
 
   // Called when data is received.
   // |stream_id| The stream receiving data.
   // |data| A buffer containing the data received.
   // |len| The length of the data buffer (at most 2^24 - 1 for SPDY/3,
@@ skipping 37 matching lines @@
                         SpdyGoAwayStatus status,
                         base::StringPiece debug_data) = 0;
 
   // Called when a WINDOW_UPDATE frame has been parsed.
   virtual void OnWindowUpdate(SpdyStreamId stream_id,
                               int delta_window_size) = 0;
 
   // Called when a PUSH_PROMISE frame has been parsed.
   virtual void OnPushPromise(SpdyStreamId stream_id,
                              SpdyStreamId promised_stream_id,
-                             const SpdyHeaderBlock& headers) = 0;
+                             SpdyHeaderBlock headers) = 0;
 
   // Called when an ALTSVC frame has been parsed.
   virtual void OnAltSvc(
       SpdyStreamId stream_id,
       base::StringPiece origin,
       const SpdyAltSvcWireFormat::AlternativeServiceVector& altsvc_vector) = 0;
 
   // Called when a frame type we don't recognize is received.
   // Return true if this appears to be a valid extension frame, false otherwise.
   // We distinguish between extension frames and nonsense by checking
@@ skipping 172 matching lines @@
   std::unique_ptr<GoAwayFields> goaway_fields_;
 
   std::unique_ptr<HeaderCoalescer> coalescer_;
 
   DISALLOW_COPY_AND_ASSIGN(BufferedSpdyFramer);
 };
 
 }  // namespace net
 
 #endif  // NET_SPDY_BUFFERED_SPDY_FRAMER_H_