Use the location where FileDescriptorWatcher is created to track the libevent handlers

ui/events/ozone/device/udev/device_manager_udev.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 "ui/events/ozone/device/udev/device_manager_udev.h"
 
 #include <stddef.h>
 
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
@@ skipping 64 matching lines @@
       LOG(ERROR) << "Failed to start receiving events from udev";
   } else {
     LOG(ERROR) << "Failed to create udev monitor";
   }
 
   return device::ScopedUdevMonitorPtr(monitor);
 }
 
 }  // namespace
 
-DeviceManagerUdev::DeviceManagerUdev() : udev_(UdevCreate()) {
-}
+DeviceManagerUdev::DeviceManagerUdev()
+    : udev_(UdevCreate()), controller_(FROM_HERE) {}
 
 DeviceManagerUdev::~DeviceManagerUdev() {
 }
 
 void DeviceManagerUdev::CreateMonitor() {
   if (monitor_)
     return;
   monitor_ = UdevCreateMonitor(udev_.get());
   if (monitor_) {
     int fd = device::udev_monitor_get_fd(monitor_.get());
@@ skipping 88 matching lines @@
   else if (!strcmp(action, "change"))
     action_type = DeviceEvent::CHANGE;
   else
     return nullptr;
 
   return base::MakeUnique<DeviceEvent>(device_type, action_type,
                                        base::FilePath(path));
 }
 
 }  // namespace ui