Adding instrumentation to locate the source of jankiness.

content/browser/loader/resource_loader.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 "content/browser/loader/resource_loader.h"
 
 #include "base/command_line.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/profiler/scoped_tracker.h"
@@ skipping 128 matching lines @@
   ResourceRequestInfoImpl* info = GetRequestInfo();
   info->set_was_ignored_by_handler(true);
   CancelRequest(false);
 }
 
 void ResourceLoader::CancelWithError(int error_code) {
   CancelRequestInternal(error_code, false);
 }
 
 void ResourceLoader::ReportUploadProgress() {
+  // TODO(pkasting): Remove ScopedTracker below once crbug.com/455952 is
+  // fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "455952 ResourceLoader::ReportUploadProgress"));
   if (waiting_for_upload_progress_ack_)
     return;  // Send one progress event at a time.
 
   net::UploadProgress progress = request_->GetUploadProgress();
   if (!progress.size())
     return;  // Nothing to upload.
 
   if (progress.position() == last_upload_position_)
     return;  // No progress made since last time.
 
@@ skipping 691 matching lines @@
     UMA_HISTOGRAM_ENUMERATION("Net.Prefetch.Pattern", status, STATUS_MAX);
   }
 }
 
 void ResourceLoader::ContinueWithCertificate(net::X509Certificate* cert) {
   ssl_client_auth_handler_.reset();
   request_->ContinueWithCertificate(cert);
 }
 
 }  // namespace content