Adding instrumentation to locate the source of jankiness.

content/browser/service_worker/service_worker_url_request_job.cc

 // Copyright 2014 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/service_worker/service_worker_url_request_job.h"
 
 #include <map>
 #include <string>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/guid.h"
+#include "base/profiler/scoped_tracker.h"
 #include "base/strings/stringprintf.h"
 #include "base/time/time.h"
 #include "content/browser/service_worker/service_worker_fetch_dispatcher.h"
 #include "content/browser/service_worker/service_worker_provider_host.h"
 #include "content/common/resource_request_body.h"
 #include "content/common/service_worker/service_worker_types.h"
 #include "content/public/browser/blob_handle.h"
 #include "content/public/browser/resource_request_info.h"
 #include "content/public/browser/service_worker_context.h"
 #include "net/base/net_errors.h"
@@ skipping 146 matching lines @@
     bool fatal) {
   NOTREACHED();
 }
 
 void ServiceWorkerURLRequestJob::OnBeforeNetworkStart(net::URLRequest* request,
                                                       bool* defer) {
   NOTREACHED();
 }
 
 void ServiceWorkerURLRequestJob::OnResponseStarted(net::URLRequest* request) {
+  // TODO(vadimt): Remove ScopedTracker below once crbug.com/423948 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "423948 ServiceWorkerURLRequestJob::OnResponseStarted"));
+
   // TODO(falken): Add Content-Length, Content-Type if they were not provided in
   // the ServiceWorkerResponse.
   response_time_ = base::Time::Now();
   CommitResponseHeader();
 }
 
 void ServiceWorkerURLRequestJob::OnReadCompleted(net::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 ServiceWorkerURLRequestJob::OnReadCompleted"));
+
   SetStatus(request->status());
   if (!request->status().is_success()) {
     NotifyDone(request->status());
     return;
   }
   NotifyReadComplete(bytes_read);
   if (bytes_read == 0)
     NotifyDone(request->status());
 }
 
@@ skipping 283 matching lines @@
 
 void ServiceWorkerURLRequestJob::DeliverErrorResponse() {
   // TODO(falken): Print an error to the console of the ServiceWorker and of
   // the requesting page.
   CreateResponseHeader(
       500, "Service Worker Response Error", ServiceWorkerHeaderMap());
   CommitResponseHeader();
 }
 
 }  // namespace content