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

net/tools/quic/quic_spdy_client_stream.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/tools/quic/quic_spdy_client_stream.h"
 
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
 #include "net/quic/quic_alarm.h"
@@ skipping 121 matching lines @@
   SpdyHeaderBlock promise_headers;
   if (!SpdyUtils::CopyAndValidateHeaders(header_list, &content_length,
                                          &promise_headers)) {
     DLOG(ERROR) << "Failed to parse promise headers: "
                 << header_list.DebugString();
     Reset(QUIC_BAD_APPLICATION_PAYLOAD);
     return;
   }
 
   session_->HandlePromised(id(), promised_id, promise_headers);
+  if (visitor() != nullptr) {
+    visitor()->OnPromiseHeadersComplete(promised_id, frame_len);
+  }
 }
 
 void QuicSpdyClientStream::OnDataAvailable() {
   if (FLAGS_quic_supports_push_promise) {
     // For push streams, visitor will not be set until the rendezvous
     // between server promise and client request is complete.
     if (visitor() == nullptr)
       return;
   }
 
@@ skipping 32 matching lines @@
   bytes_sent += header_bytes_written_;
 
   if (!body.empty()) {
     WriteOrBufferData(body, fin, nullptr);
   }
 
   return bytes_sent;
 }
 
 }  // namespace net