[Not for review] Add TRACE_EVENTs and chrome://flags for preconnect

net/quic/chromium/quic_stream_factory.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/quic/chromium/quic_stream_factory.h"
 
 #include <algorithm>
 #include <tuple>
 #include <utility>
 
@@ skipping 519 matching lines @@
 
   if (!session_->connection()->connected() &&
       session_->error() == QUIC_PROOF_INVALID) {
     return ERR_QUIC_HANDSHAKE_FAILED;
   }
 
   return rv;
 }
 
 int QuicStreamFactory::Job::DoConnectComplete(int rv) {
+  TRACE_EVENT1(kNetTracingCategory, "QuicStreamFactory::Job::DoConnectComplete",
+               "host", key_.destination().host());
   net_log_.EndEvent(NetLogEventType::QUIC_STREAM_FACTORY_JOB_CONNECT);
   if (session_ && session_->error() == QUIC_CRYPTO_HANDSHAKE_STATELESS_REJECT) {
     num_sent_client_hellos_ += session_->GetNumSentClientHellos();
     if (num_sent_client_hellos_ >= QuicCryptoClientStream::kMaxClientHellos)
       return ERR_QUIC_HANDSHAKE_FAILED;
     // The handshake was rejected statelessly, so create another connection
     // to resume the handshake.
     io_state_ = STATE_CONNECT;
     return OK;
   }
@@ skipping 30 matching lines @@
     factory_->CancelRequest(this);
 }
 
 int QuicStreamRequest::Request(const HostPortPair& destination,
                                PrivacyMode privacy_mode,
                                int cert_verify_flags,
                                const GURL& url,
                                QuicStringPiece method,
                                const NetLogWithSource& net_log,
                                const CompletionCallback& callback) {
+  TRACE_EVENT1(kNetTracingCategory, "QuicStreamRequest::Request", "host",
+               destination.host());
   DCHECK(callback_.is_null());
   DCHECK(factory_);
   server_id_ = QuicServerId(HostPortPair::FromURL(url), privacy_mode);
 
   int rv = factory_->Create(server_id_, destination, cert_verify_flags, url,
                             method, net_log, this);
   if (rv == ERR_IO_PENDING) {
     net_log_ = net_log;
     callback_ = callback;
   } else {
@@ skipping 1100 matching lines @@
   // Since the session was active, there's no longer an
   // HttpStreamFactoryImpl::Job running which can mark it broken, unless the TCP
   // job also fails. So to avoid not using QUIC when we otherwise could, we mark
   // it as recently broken, which means that 0-RTT will be disabled but we'll
   // still race.
   http_server_properties_->MarkAlternativeServiceRecentlyBroken(
       alternative_service);
 }
 
 }  // namespace net