Adding instrumentation to locate the source of jankiness.

net/url_request/sdch_dictionary_fetcher.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 "net/url_request/sdch_dictionary_fetcher.h"
 
 #include <stdint.h>
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/compiler_specific.h"
+#include "base/profiler/scoped_tracker.h"
 #include "base/thread_task_runner_handle.h"
 #include "net/base/load_flags.h"
 #include "net/url_request/url_request_context.h"
 #include "net/url_request/url_request_status.h"
 #include "net/url_request/url_request_throttler_manager.h"
 
 namespace {
 
 const int kBufferSize = 4096;
 
@@ skipping 52 matching lines @@
   while (!fetch_queue_.empty())
     fetch_queue_.pop();
   attempted_load_.clear();
   weak_factory_.InvalidateWeakPtrs();
   current_request_.reset(NULL);
   buffer_ = NULL;
   dictionary_.clear();
 }
 
 void SdchDictionaryFetcher::OnResponseStarted(URLRequest* request) {
+  // TODO(vadimt): Remove ScopedTracker below once crbug.com/423948 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "423948 SdchDictionaryFetcher::OnResponseStarted"));
+
   DCHECK(CalledOnValidThread());
   DCHECK_EQ(request, current_request_.get());
   DCHECK_EQ(next_state_, STATE_REQUEST_STARTED);
 
   // The response has started, so the stream can be read from.
   next_state_ = STATE_REQUEST_READING;
 
   // If this function was synchronously called, the containing
   // state machine loop will handle the state transition. Otherwise,
   // restart the state machine loop.
   if (in_loop_)
     return;
 
   DoLoop(request->status().error());
 }
 
 void SdchDictionaryFetcher::OnReadCompleted(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 SdchDictionaryFetcher::OnReadCompleted"));
+
   DCHECK(CalledOnValidThread());
   DCHECK_EQ(request, current_request_.get());
   DCHECK_EQ(next_state_, STATE_REQUEST_READING);
 
   // No state transition is required in this function; the
   // completion of the request is detected in DoRead().
 
   if (request->status().is_success())
     dictionary_.append(buffer_->data(), bytes_read);
 
@@ skipping 122 matching lines @@
   current_request_.reset();
   buffer_ = NULL;
   dictionary_.clear();
 
   next_state_ = STATE_IDLE;
 
   return OK;
 }
 
 }  // namespace net