Adding instrumentation to locate the source of jankiness.

sync/internal_api/http_bridge.cc

 // Copyright 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 "sync/internal_api/public/http_bridge.h"
 
 #include "base/message_loop/message_loop.h"
+#include "base/profiler/scoped_profile.h"
 #include "base/strings/string_number_conversions.h"
 #include "net/base/load_flags.h"
 #include "net/base/net_errors.h"
 #include "net/cookies/cookie_monster.h"
 #include "net/http/http_cache.h"
 #include "net/http/http_network_layer.h"
 #include "net/http/http_response_headers.h"
 #include "net/url_request/static_http_user_agent_settings.h"
 #include "net/url_request/url_fetcher.h"
 #include "net/url_request/url_request_context.h"
@@ skipping 319 matching lines @@
   fetch_state_.error_code = net::ERR_ABORTED;
   http_post_completed_.Signal();
 }
 
 void HttpBridge::DestroyURLFetcherOnIOThread(net::URLFetcher* fetcher) {
   DCHECK(network_task_runner_->BelongsToCurrentThread());
   delete fetcher;
 }
 
 void HttpBridge::OnURLFetchComplete(const net::URLFetcher* source) {
+  // TODO(vadimt): Remove ScopedProfile below once crbug.com/422577 is fixed.
+  tracked_objects::ScopedProfile tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "422577 HttpBridge::OnURLFetchComplete"));
+
   DCHECK(network_task_runner_->BelongsToCurrentThread());
   base::AutoLock lock(fetch_state_lock_);
   if (fetch_state_.aborted)
     return;
 
   fetch_state_.end_time = base::Time::Now();
   fetch_state_.request_completed = true;
   fetch_state_.request_succeeded =
       (net::URLRequestStatus::SUCCESS == source->GetStatus().status());
   fetch_state_.http_response_code = source->GetResponseCode();
@@ skipping 38 matching lines @@
   int64 sane_time_ms = 0;
   if (base::StringToInt64(sane_time_str, &sane_time_ms)) {
     network_time_update_callback_.Run(
         base::Time::FromJsTime(sane_time_ms),
         base::TimeDelta::FromMilliseconds(1),
         fetch_state_.end_time - fetch_state_.start_time);
   }
 }
 
 }  // namespace syncer