Remove Task inheritance from base::Timer.

base/timer.cc

Index: base/timer.cc
diff --git a/base/timer.cc b/base/timer.cc
index 8c06693a6c9ae2bff1b63260bb903a3f0df9de13..0c2349622f42555df97cf4adee172660084b1d8d 100644
--- a/base/timer.cc
+++ b/base/timer.cc
@@ -4,6 +4,8 @@
 
 #include "base/timer.h"
 
+#include "base/bind.h"
+#include "base/bind_helpers.h"
 #include "base/message_loop.h"
 
 namespace base {
@@ -21,7 +23,8 @@ void BaseTimer_Helper::InitiateDelayedTask(TimerTask* timer_task) {
   delayed_task_ = timer_task;
   delayed_task_->timer_ = this;
   MessageLoop::current()->PostDelayedTask(
-      timer_task->posted_from_, timer_task,
+      timer_task->posted_from_,
+      base::Bind(&TimerTask::Run, base::Unretained(timer_task)),
       static_cast<int>(timer_task->delay_.InMillisecondsRoundedUp()));
 }