MessageLoop's RUN method will pass a const ref to PendingTask when

base/message_loop.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 "base/message_loop.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
@@ skipping 454 matching lines @@
   const void* program_counter =
       pending_task.posted_from.program_counter();
   base::debug::Alias(&program_counter);
 
   HistogramEvent(kTaskRunEvent);
 
   tracked_objects::TrackedTime start_time =
       tracked_objects::ThreadData::NowForStartOfRun(pending_task.birth_tally);
 
   FOR_EACH_OBSERVER(TaskObserver, task_observers_,
-                    WillProcessTask(pending_task.time_posted));
+                    WillProcessTask(pending_task));
   pending_task.task.Run();
   FOR_EACH_OBSERVER(TaskObserver, task_observers_,
-                    DidProcessTask(pending_task.time_posted));
+                    DidProcessTask(pending_task));
 
   tracked_objects::ThreadData::TallyRunOnNamedThreadIfTracking(pending_task,
       start_time, tracked_objects::ThreadData::NowForEndOfRun());
 
   nestable_tasks_allowed_ = true;
 }
 
 bool MessageLoop::DeferOrRunPendingTask(const PendingTask& pending_task) {
   if (pending_task.nestable || run_loop_->run_depth_ == 1) {
     RunTask(pending_task);
@@ skipping 317 matching lines @@
                                            Watcher *delegate) {
   return pump_libevent()->WatchFileDescriptor(
       fd,
       persistent,
       mode,
       controller,
       delegate);
 }
 
 #endif