Modernize TimerTests prior to https://codereview.chromium.org/2491613004

base/timer/timer.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/timer/timer.h"
 
 #include <stddef.h>
 
 #include <utility>
 
@@ skipping 163 matching lines @@
         base::Bind(&BaseTimerTaskInternal::Run, base::Owned(scheduled_task_)),
         delay);
     scheduled_run_time_ = desired_run_time_ = Now() + delay;
   } else {
     GetTaskRunner()->PostTask(posted_from_,
         base::Bind(&BaseTimerTaskInternal::Run, base::Owned(scheduled_task_)));
     scheduled_run_time_ = desired_run_time_ = TimeTicks();
   }
   // Remember the thread ID that posts the first task -- this will be verified
   // later when the task is abandoned to detect misuse from multiple threads.
-  if (!thread_id_) {
-    DCHECK(GetTaskRunner()->BelongsToCurrentThread());
+  if (!thread_id_)
     thread_id_ = static_cast<int>(PlatformThread::CurrentId());
-  }
 }
 
 scoped_refptr<SingleThreadTaskRunner> Timer::GetTaskRunner() {
   return task_runner_.get() ? task_runner_ : ThreadTaskRunnerHandle::Get();
 }
 
 void Timer::AbandonScheduledTask() {
   DCHECK(thread_id_ == 0 ||
          thread_id_ == static_cast<int>(PlatformThread::CurrentId()));
   if (scheduled_task_) {
@@ skipping 29 matching lines @@
     PostNewScheduledTask(delay_);
   else
     Stop();
 
   task.Run();
 
   // No more member accesses here: *this could be deleted at this point.
 }
 
 }  // namespace base