Update from https://crrev.com/306655

net/dns/single_request_host_resolver.cc

 // Copyright (c) 2011 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/dns/single_request_host_resolver.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
+#include "base/profiler/scoped_tracker.h"
 #include "net/base/net_errors.h"
 
 namespace net {
 
 SingleRequestHostResolver::SingleRequestHostResolver(HostResolver* resolver)
     : resolver_(resolver),
       cur_request_(NULL),
       callback_(
           base::Bind(&SingleRequestHostResolver::OnResolveCompletion,
                      base::Unretained(this))) {
@@ skipping 35 matching lines @@
 
 void SingleRequestHostResolver::Cancel() {
   if (!cur_request_callback_.is_null()) {
     resolver_->CancelRequest(cur_request_);
     cur_request_ = NULL;
     cur_request_callback_.Reset();
   }
 }
 
 void SingleRequestHostResolver::OnResolveCompletion(int result) {
+  // TODO(vadimt): Remove ScopedTracker below once crbug.com/436634 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "436634 SingleRequestHostResolver::OnResolveCompletion"));
+
   DCHECK(cur_request_);
   DCHECK_EQ(false, cur_request_callback_.is_null());
 
   CompletionCallback callback = cur_request_callback_;
 
   // Clear the outstanding request information.
   cur_request_ = NULL;
   cur_request_callback_.Reset();
 
   // Call the user's original callback.
   callback.Run(result);
 }
 
 }  // namespace net