Adding instrumentation to locate the source of jankiness.

net/proxy/polling_proxy_config_service.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/proxy/polling_proxy_config_service.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "base/observer_list.h"
+#include "base/profiler/scoped_tracker.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/worker_pool.h"
 #include "net/proxy/proxy_config.h"
 
 namespace net {
 
 // Reference-counted wrapper that does all the work (needs to be
 // reference-counted since we post tasks between threads; may outlive
 // the parent PollingProxyConfigService).
 class PollingProxyConfigService::Core
@@ skipping 84 matching lines @@
 
     base::AutoLock l(lock_);
     if (origin_loop_proxy_.get()) {
       origin_loop_proxy_->PostTask(
           FROM_HERE, base::Bind(&Core::GetConfigCompleted, this, config));
     }
   }
 
   // Called after the worker thread has finished retrieving a configuration.
   void GetConfigCompleted(const ProxyConfig& config) {
+    // TODO(pkasting): Remove ScopedTracker below once crbug.com/455942 is
+    // fixed.
+    tracked_objects::ScopedTracker tracking_profile(
+        FROM_HERE_WITH_EXPLICIT_FUNCTION(
+            "455942 PollingProxyConfigService::Core::GetConfigCompleted"));
     DCHECK(poll_task_outstanding_);
     poll_task_outstanding_ = false;
 
     if (!origin_loop_proxy_.get())
       return;  // Was orphaned (parent has already been destroyed).
 
     DCHECK(origin_loop_proxy_->BelongsToCurrentThread());
 
     if (!has_config_ || !last_config_.Equals(config)) {
       // If the configuration has changed, notify the observers.
@@ skipping 59 matching lines @@
 
 PollingProxyConfigService::~PollingProxyConfigService() {
   core_->Orphan();
 }
 
 void PollingProxyConfigService::CheckForChangesNow() {
   core_->CheckForChangesNow();
 }
 
 }  // namespace net