Adding instrumentation to locate the source of jankiness.

net/proxy/proxy_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/proxy_service.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/message_loop/message_loop_proxy.h"
+#include "base/profiler/scoped_tracker.h"
 #include "base/strings/string_util.h"
 #include "base/thread_task_runner_handle.h"
 #include "base/values.h"
 #include "net/base/completion_callback.h"
 #include "net/base/load_flags.h"
 #include "net/base/net_errors.h"
 #include "net/base/net_log.h"
 #include "net/base/net_util.h"
 #include "net/proxy/dhcp_proxy_script_fetcher.h"
 #include "net/proxy/multi_threaded_proxy_resolver.h"
@@ skipping 1446 matching lines @@
 
 // static
 scoped_ptr<ProxyService::PacPollPolicy>
   ProxyService::CreateDefaultPacPollPolicy() {
   return scoped_ptr<PacPollPolicy>(new DefaultPollPolicy());
 }
 
 void ProxyService::OnProxyConfigChanged(
     const ProxyConfig& config,
     ProxyConfigService::ConfigAvailability availability) {
+  // TODO(pkasting): Remove ScopedTracker below once crbug.com/455942 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "455942 ProxyService::OnProxyConfigChanged"));
   // Retrieve the current proxy configuration from the ProxyConfigService.
   // If a configuration is not available yet, we will get called back later
   // by our ProxyConfigService::Observer once it changes.
   ProxyConfig effective_config;
   switch (availability) {
     case ProxyConfigService::CONFIG_PENDING:
       // ProxyConfigService implementors should never pass CONFIG_PENDING.
       NOTREACHED() << "Proxy config change with CONFIG_PENDING availability!";
       return;
     case ProxyConfigService::CONFIG_VALID:
@@ skipping 88 matching lines @@
   State previous_state = ResetProxyConfig(false);
   if (previous_state != STATE_NONE)
     ApplyProxyConfigIfAvailable();
 }
 
 void ProxyService::OnDNSChanged() {
   OnIPAddressChanged();
 }
 
 }  // namespace net