Avoid SpdyHeaderBlock copy in SpdyStream::OnPushPromiseHeadersReceived().

net/spdy/spdy_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/spdy/spdy_stream.h"
 
 #include <limits>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 447 matching lines @@
   if (type_ == SPDY_PUSH_STREAM &&
       response_headers_status_ == RESPONSE_HEADERS_ARE_COMPLETE) {
     session_->ResetStream(
         stream_id_, RST_STREAM_PROTOCOL_ERROR,
         "Additional headers received for push stream");
     return ERR_SPDY_PROTOCOL_ERROR;
   }
   return MergeWithResponseHeaders(additional_response_headers);
 }
 
-void SpdyStream::OnPushPromiseHeadersReceived(const SpdyHeaderBlock& headers) {
+void SpdyStream::OnPushPromiseHeadersReceived(SpdyHeaderBlock headers) {
   CHECK(!request_headers_valid_);
   CHECK_EQ(io_state_, STATE_IDLE);
   CHECK_EQ(type_, SPDY_PUSH_STREAM);
   DCHECK(!delegate_);
 
   io_state_ = STATE_RESERVED_REMOTE;
-  request_headers_ = headers.Clone();
+  request_headers_ = std::move(headers);
   request_headers_valid_ = true;
   url_from_header_block_ = GetUrlFromHeaderBlock(request_headers_);
 }
 
 void SpdyStream::OnDataReceived(std::unique_ptr<SpdyBuffer> buffer) {
   DCHECK(session_->IsStreamActive(stream_id_));
 
   // Track our bandwidth.
   recv_bytes_ += buffer ? buffer->GetRemainingSize() : 0;
   recv_last_byte_time_ = base::TimeTicks::Now();
@@ skipping 445 matching lines @@
       description = base::StringPrintf("Unknown state 0x%08X (%u)", state,
                                        state);
       break;
   }
   return description;
 }
 
 #undef STATE_CASE
 
 }  // namespace net