Adding instrumentation to locate the source of jankiness.

content/browser/loader/power_save_block_resource_throttle.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 "content/browser/loader/power_save_block_resource_throttle.h"
 
+#include "base/profiler/scoped_tracker.h"
 #include "content/public/browser/power_save_blocker.h"
 
 namespace content {
 
 namespace {
 
 const int kPowerSaveBlockDelaySeconds = 30;
 
 }  // namespace
 
 PowerSaveBlockResourceThrottle::PowerSaveBlockResourceThrottle() {
 }
 
 PowerSaveBlockResourceThrottle::~PowerSaveBlockResourceThrottle() {
 }
 
 void PowerSaveBlockResourceThrottle::WillStartRequest(bool* defer) {
   // Delay PowerSaveBlocker activation to dismiss small requests.
   timer_.Start(FROM_HERE,
                base::TimeDelta::FromSeconds(kPowerSaveBlockDelaySeconds),
                this,
                &PowerSaveBlockResourceThrottle::ActivatePowerSaveBlocker);
 }
 
 void PowerSaveBlockResourceThrottle::WillProcessResponse(bool* defer) {
+  // TODO(vadimt): Remove ScopedTracker below once crbug.com/422516 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "422516 PowerSaveBlockResourceThrottle::WillProcessResponse"));
+
   // Stop blocking power save after request finishes.
   power_save_blocker_.reset();
   timer_.Stop();
 }
 
 const char* PowerSaveBlockResourceThrottle::GetNameForLogging() const {
   return "PowerSaveBlockResourceThrottle";
 }
 
 void PowerSaveBlockResourceThrottle::ActivatePowerSaveBlocker() {
   power_save_blocker_ = PowerSaveBlocker::Create(
       PowerSaveBlocker::kPowerSaveBlockPreventAppSuspension,
       "Uploading data.");
 }
 
 }  // namespace content