Revert of Remove ExtensionService Garbage-Collecting methods.

extensions/common/one_shot_event.h

Index: extensions/common/one_shot_event.h
diff --git a/extensions/common/one_shot_event.h b/extensions/common/one_shot_event.h
index 49031243ab9f2b712c05154618cc51b15b75e8bd..9baa152d2c5ce96924978c451efb4efd8bdb557e 100644
--- a/extensions/common/one_shot_event.h
+++ b/extensions/common/one_shot_event.h
@@ -15,7 +15,6 @@
 
 namespace base {
 class TaskRunner;
-class TimeDelta;
 }
 
 namespace tracked_objects {
@@ -56,10 +55,8 @@
   void Signal();
 
   // Scheduled |task| to be called on |runner| after is_signaled()
-  // becomes true. If called with |delay|, then the task will happen
-  // (roughly) |delay| after is_signaled(), *not* |delay| after the
-  // post. Inside |task|, if this OneShotEvent is still alive,
-  // CHECK(is_signaled()) will never fail (which implies that
+  // becomes true.  Inside |task|, if this OneShotEvent is still
+  // alive, CHECK(is_signaled()) will never fail (which implies that
   // OneShotEvent::Reset() doesn't exist).
   //
   // If |*this| is destroyed before being released, none of these
@@ -81,17 +78,9 @@
   void Post(const tracked_objects::Location& from_here,
             const base::Closure& task,
             const scoped_refptr<base::TaskRunner>& runner) const;
-  void PostDelayed(const tracked_objects::Location& from_here,
-                   const base::Closure& task,
-                   const base::TimeDelta& delay) const;
 
  private:
   struct TaskInfo;
-
-  void PostImpl(const tracked_objects::Location& from_here,
-                const base::Closure& task,
-                const scoped_refptr<base::TaskRunner>& runner,
-                const base::TimeDelta& delay) const;
 
   base::ThreadChecker thread_checker_;