Update from https://crrev.com/306655

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"
@@ skipping 418 matching lines @@
           "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) {
+    // TODO(vadimt): Remove ScopedTracker below once crbug.com/423948 is fixed.
+    tracked_objects::ScopedTracker tracking_profile1(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "423948 URLFetcherCore::OnReadCompleted1"));
+
     url_throttler_entry_ = throttler_manager->RegisterRequestUrl(url_);
   }
 
+  // TODO(vadimt): Remove ScopedTracker below once crbug.com/423948 is fixed.
+  tracked_objects::ScopedTracker tracking_profile2(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "423948 URLFetcherCore::OnReadCompleted2"));
+
   do {
     if (!request_->status().is_success() || bytes_read <= 0)
       break;
 
+    // TODO(vadimt): Remove ScopedTracker below once crbug.com/423948 is fixed.
+    tracked_objects::ScopedTracker tracking_profile3(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "423948 URLFetcherCore::OnReadCompleted3"));
+
     current_response_bytes_ += bytes_read;
     InformDelegateDownloadProgress();
 
+    // TODO(vadimt): Remove ScopedTracker below once crbug.com/423948 is fixed.
+    tracked_objects::ScopedTracker tracking_profile4(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "423948 URLFetcherCore::OnReadCompleted4"));
+
     const int result =
         WriteBuffer(new DrainableIOBuffer(buffer_.get(), bytes_read));
     if (result < 0) {
       // Write failed or waiting for write completion.
       return;
     }
   } while (request_->Read(buffer_.get(), kBufferSize, &bytes_read));
 
   const URLRequestStatus status = request_->status();
 
+  // TODO(vadimt): Remove ScopedTracker below once crbug.com/423948 is fixed.
+  tracked_objects::ScopedTracker tracking_profile5(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "423948 URLFetcherCore::OnReadCompleted5"));
+
   if (status.is_success())
     request_->GetResponseCookies(&cookies_);
 
   // See comments re: HEAD requests in ReadResponse().
   if (!status.is_io_pending() || request_type_ == URLFetcher::HEAD) {
+    // TODO(vadimt): Remove ScopedTracker below once crbug.com/423948 is fixed.
+    tracked_objects::ScopedTracker tracking_profile6(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "423948 URLFetcherCore::OnReadCompleted6"));
+
     status_ = status;
     ReleaseRequest();
 
+    // TODO(vadimt): Remove ScopedTracker below once crbug.com/423948 is fixed.
+    tracked_objects::ScopedTracker tracking_profile7(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "423948 URLFetcherCore::OnReadCompleted7"));
+
     // No more data to write.
     const int result = response_writer_->Finish(
         base::Bind(&URLFetcherCore::DidFinishWriting, this));
+
+    // TODO(vadimt): Remove ScopedTracker below once crbug.com/423948 is fixed.
+    tracked_objects::ScopedTracker tracking_profile8(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "423948 URLFetcherCore::OnReadCompleted8"));
+
     if (result != ERR_IO_PENDING)
       DidFinishWriting(result);
   }
 }
 
 void URLFetcherCore::CancelAll() {
   g_registry.Get().CancelAll();
 }
 
 int URLFetcherCore::GetNumFetcherCores() {
@@ skipping 419 matching lines @@
 }
 
 void URLFetcherCore::InformDelegateDownloadProgressInDelegateThread(
     int64 current, int64 total) {
   DCHECK(delegate_task_runner_->BelongsToCurrentThread());
   if (delegate_)
     delegate_->OnURLFetchDownloadProgress(fetcher_, current, total);
 }
 
 }  // namespace net