Update from https://crrev.com/306655

net/proxy/proxy_resolver_v8_tracing.cc

 // Copyright (c) 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.
 
 #include "net/proxy/proxy_resolver_v8_tracing.h"
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop_proxy.h"
+#include "base/profiler/scoped_tracker.h"
 #include "base/strings/stringprintf.h"
 #include "base/synchronization/cancellation_flag.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/values.h"
 #include "net/base/address_list.h"
 #include "net/base/net_errors.h"
 #include "net/base/net_log.h"
 #include "net/dns/host_resolver.h"
@@ skipping 691 matching lines @@
   }
 
   if (!blocking_dns_) {
     // The worker thread always blocks waiting to see if the result can be
     // serviced from cache before restarting.
     event_.Signal();
   }
 }
 
 void ProxyResolverV8Tracing::Job::OnDnsOperationComplete(int result) {
+  // TODO(vadimt): Remove ScopedTracker below once crbug.com/436634 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "436634 ProxyResolverV8Tracing::Job::OnDnsOperationComplete"));
+
   CheckIsOnOriginThread();
 
   DCHECK(!cancelled_.IsSet());
   DCHECK(pending_dns_completed_synchronously_ == (pending_dns_ == NULL));
 
   SaveDnsToLocalCache(pending_dns_host_, pending_dns_op_, result,
                       pending_dns_addresses_);
   pending_dns_ = NULL;
 
   if (blocking_dns_) {
@@ skipping 271 matching lines @@
   DCHECK(!set_pac_script_job_.get());
   CHECK_EQ(0, num_outstanding_callbacks_);
 
   set_pac_script_job_ = new Job(this);
   set_pac_script_job_->StartSetPacScript(script_data, callback);
 
   return ERR_IO_PENDING;
 }
 
 }  // namespace net