Update from https://crrev.com/304715

net/url_request/url_fetcher_core.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/url_request/url_fetcher_core.h"
 
 #include <stdint.h>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/metrics/histogram.h"
+#include "base/profiler/scoped_tracker.h"
 #include "base/sequenced_task_runner.h"
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/tracked_objects.h"
 #include "net/base/elements_upload_data_stream.h"
 #include "net/base/io_buffer.h"
 #include "net/base/load_flags.h"
 #include "net/base/net_errors.h"
 #include "net/base/request_priority.h"
@@ skipping 360 matching lines @@
     stopped_on_redirect_ = true;
     url_ = redirect_info.new_url;
     response_code_ = request_->GetResponseCode();
     was_fetched_via_proxy_ = request_->was_fetched_via_proxy();
     request->Cancel();
     OnReadCompleted(request, 0);
   }
 }
 
 void URLFetcherCore::OnResponseStarted(URLRequest* request) {
+  // TODO(vadimt): Remove ScopedTracker below once crbug.com/423948 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "423948 URLFetcherCore::OnResponseStarted"));
+
   DCHECK_EQ(request, request_.get());
   DCHECK(network_task_runner_->BelongsToCurrentThread());
   if (request_->status().is_success()) {
     response_code_ = request_->GetResponseCode();
     response_headers_ = request_->response_headers();
     socket_address_ = request_->GetSocketAddress();
     was_fetched_via_proxy_ = request_->was_fetched_via_proxy();
     total_response_bytes_ = request_->GetExpectedContentSize();
   }
 
   ReadResponse();
 }
 
 void URLFetcherCore::OnCertificateRequested(
     URLRequest* request,
     SSLCertRequestInfo* cert_request_info) {
   DCHECK_EQ(request, request_.get());
   DCHECK(network_task_runner_->BelongsToCurrentThread());
 
   if (g_ignore_certificate_requests) {
     request->ContinueWithCertificate(NULL);
   } else {
     request->Cancel();
   }
 }
 
 void URLFetcherCore::OnReadCompleted(URLRequest* request,
                                      int bytes_read) {
+  // TODO(vadimt): Remove ScopedTracker below once crbug.com/423948 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "423948 URLFetcherCore::OnReadCompleted"));
+
   DCHECK(request == request_);
   DCHECK(network_task_runner_->BelongsToCurrentThread());
 
   if (!stopped_on_redirect_)
     url_ = request->url();
   URLRequestThrottlerManager* throttler_manager =
       request->context()->throttler_manager();
   if (throttler_manager) {
     url_throttler_entry_ = throttler_manager->RegisterRequestUrl(url_);
   }
@@ skipping 458 matching lines @@
 }
 
 void URLFetcherCore::InformDelegateDownloadProgressInDelegateThread(
     int64 current, int64 total) {
   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
   if (delegate_)
     delegate_->OnURLFetchDownloadProgress(fetcher_, current, total);
 }
 
 }  // namespace net