Instrumenting Predictor::StartSomeQueuedResolutions and ProfileIOData::Init to find jank

chrome/browser/net/predictor.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 "chrome/browser/net/predictor.h"
 
 #include <algorithm>
 #include <cmath>
 #include <set>
 #include <sstream>
@@ skipping 1148 matching lines @@
     info->SetAssignedState();
   }
   return true;
 }
 
 void Predictor::StartSomeQueuedResolutions() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   while (!work_queue_.IsEmpty() &&
          pending_lookups_.size() < max_concurrent_dns_lookups_) {
+    // TODO(vadimt): Remove ScopedTracker below once crbug.com/436671 is fixed.
+    tracked_objects::ScopedTracker tracking_profile1(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "436671 Predictor::StartSomeQueuedResolutions1"));
+
     const GURL url(work_queue_.Pop());
     UrlInfo* info = &results_[url];
     DCHECK(info->HasUrl(url));
     info->SetAssignedState();
 
     if (CongestionControlPerformed(info)) {
       DCHECK(work_queue_.IsEmpty());
       return;
     }
 
     LookupRequest* request = new LookupRequest(this, host_resolver_, url);
+
+    // TODO(vadimt): Remove ScopedTracker below once crbug.com/436671 is fixed.
+    tracked_objects::ScopedTracker tracking_profile2(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "436671 Predictor::StartSomeQueuedResolutions2"));
+
     int status = request->Start();
+
+    // TODO(vadimt): Remove ScopedTracker below once crbug.com/436671 is fixed.
+    tracked_objects::ScopedTracker tracking_profile3(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "436671 Predictor::StartSomeQueuedResolutions3"));
+
     if (status == net::ERR_IO_PENDING) {
       // Will complete asynchronously.
       pending_lookups_.insert(request);
       peak_pending_lookups_ = std::max(peak_pending_lookups_,
                                        pending_lookups_.size());
     } else {
       // Completed synchronously (was already cached by HostResolver), or else
       // there was (equivalently) some network error that prevents us from
       // finding the name.  Status net::OK means it was "found."
       LookupFinished(request, url, status == net::OK);
@@ skipping 213 matching lines @@
 }
 
 void SimplePredictor::ShutdownOnUIThread() {
   SetShutdown(true);
 }
 
 bool SimplePredictor::CanPrefetchAndPrerender() const { return true; }
 bool SimplePredictor::CanPreresolveAndPreconnect() const { return true; }
 
 }  // namespace chrome_browser_net