Update from https://crrev.com/315085

net/socket/client_socket_pool_base.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/socket/client_socket_pool_base.h"
 
 #include "base/compiler_specific.h"
 #include "base/format_macros.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 1108 matching lines @@
   CHECK(!ContainsKey(pending_callback_map_, handle));
   pending_callback_map_[handle] = CallbackResultPair(callback, rv);
   base::MessageLoop::current()->PostTask(
       FROM_HERE,
       base::Bind(&ClientSocketPoolBaseHelper::InvokeUserCallback,
                  weak_factory_.GetWeakPtr(), handle));
 }
 
 void ClientSocketPoolBaseHelper::InvokeUserCallback(
     ClientSocketHandle* handle) {
+  // TODO(pkasting): Remove ScopedTracker below once crbug.com/455884 is fixed.
+  tracked_objects::ScopedTracker tracking_profile(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "455884 ClientSocketPoolBaseHelper::InvokeUserCallback"));
   PendingCallbackMap::iterator it = pending_callback_map_.find(handle);
 
   // Exit if the request has already been cancelled.
   if (it == pending_callback_map_.end())
     return;
 
   CHECK(!handle->is_initialized());
   CompletionCallback callback = it->second.callback;
   int result = it->second.result;
   pending_callback_map_.erase(it);
@@ skipping 189 matching lines @@
   pending_requests_.Erase(pointer);
   // If there are no more requests, kill the backup timer.
   if (pending_requests_.empty())
     backup_job_timer_.Stop();
   return request.Pass();
 }
 
 }  // namespace internal
 
 }  // namespace net