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

dbus/bus.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 "dbus/bus.h"
 
 #include <stddef.h>
 
 #include "base/bind.h"
 #include "base/logging.h"
@@ skipping 27 matching lines @@
 const char kServiceNameOwnerChangeMatchRule[] =
     "type='signal',interface='org.freedesktop.DBus',"
     "member='NameOwnerChanged',path='/org/freedesktop/DBus',"
     "sender='org.freedesktop.DBus',arg0='%s'";
 
 // The class is used for watching the file descriptor used for D-Bus
 // communication.
 class Watch : public base::MessagePumpLibevent::Watcher {
  public:
   explicit Watch(DBusWatch* watch)
-      : raw_watch_(watch) {
+      : raw_watch_(watch), file_descriptor_watcher_(FROM_HERE) {
     dbus_watch_set_data(raw_watch_, this, NULL);
   }
 
   ~Watch() override { dbus_watch_set_data(raw_watch_, NULL, NULL); }
 
   // Returns true if the underlying file descriptor is ready to be watched.
   bool IsReadyToBeWatched() {
     return dbus_watch_get_enabled(raw_watch_);
   }
 
@@ skipping 1150 matching lines @@
                              kNameOwnerChangedSignal)) {
     Bus* self = static_cast<Bus*>(data);
     self->OnServiceOwnerChanged(message);
   }
   // Always return unhandled to let others, e.g. ObjectProxies, handle the same
   // signal.
   return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 }
 
 }  // namespace dbus