Revert of Remove ExtensionService Garbage-Collecting methods.

extensions/common/one_shot_event.h

 // Copyright 2013 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.
 
 #ifndef EXTENSIONS_COMMON_ONE_SHOT_EVENT_H_
 #define EXTENSIONS_COMMON_ONE_SHOT_EVENT_H_
 
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/thread_checker.h"
 
 namespace base {
 class TaskRunner;
-class TimeDelta;
 }
 
 namespace tracked_objects {
 class Location;
 }
 
 namespace extensions {
 
 // This class represents an event that's expected to happen once.  It
 // allows clients to guarantee that code is run after the OneShotEvent
@@ skipping 20 matching lines @@
   bool is_signaled() const {
     DCHECK(thread_checker_.CalledOnValidThread());
     return signaled_;
   }
 
   // Causes is_signaled() to return true and all queued tasks to be
   // run in an arbitrary order.  This method must only be called once.
   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
   // tasks will be executed.
   //
   // Omitting the |runner| argument indicates that |task| should run
   // on MessageLoopProxy::current().
   //
   // Tasks may be run in an arbitrary order, not just FIFO.  Tasks
   // will never be called on the current thread before this function
   // returns.  Beware that there's no simple way to wait for all tasks
   // on a OneShotEvent to complete, so it's almost never safe to use
   // base::Unretained() when creating one.
   //
   // Const because Post() doesn't modify the logical state of this
   // object (which is just the is_signaled() bit).
   void Post(const tracked_objects::Location& from_here,
             const base::Closure& task) const;
   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_;
 
   bool signaled_;
 
   // The task list is mutable because it's not part of the logical
   // state of the object.  This lets us return const references to the
   // OneShotEvent to clients that just want to run tasks through it
   // without worrying that they'll signal the event.
   //
   // Optimization note: We could reduce the size of this class to a
   // single pointer by storing |signaled_| in the low bit of a
   // pointer, and storing the size and capacity of the array (if any)
   // on the far end of the pointer.
   mutable std::vector<TaskInfo> tasks_;
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_COMMON_ONE_SHOT_EVENT_H_