Optimize posting of WTF::Closure and improve scheduler test mocks

third_party/WebKit/Source/platform/scheduler/base/cancelable_closure_holder.h

 // Copyright 2014 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 THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_CANCELABLE_CLOSURE_HOLDER_H_
 #define THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_CANCELABLE_CLOSURE_HOLDER_H_
 
 #include "base/cancelable_callback.h"
 #include "base/macros.h"
 
 namespace blink {
 namespace scheduler {
 
 // A CancelableClosureHolder is a CancelableCallback which resets its wrapped
 // callback with a cached closure whenever it is canceled.
+// TODO(alexclarke): Remove this in favor of native cancellable tasks.
 class CancelableClosureHolder {
  public:
   CancelableClosureHolder();
   ~CancelableClosureHolder();
 
   // Resets the closure to be wrapped by the cancelable callback.  Cancels any
   // outstanding callbacks.
   void Reset(const base::Closure& callback);
 
   // Cancels any outstanding closures returned by callback().
   void Cancel();
 
   // Returns a callback that will be disabled by calling Cancel(). Callback
   // must have been set using Reset() before calling this function.
   const base::Closure& callback() const;
 
  private:
   base::Closure callback_;
   base::CancelableClosure cancelable_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(CancelableClosureHolder);
 };
 
 }  // namespace scheduler
 }  // namespace blink
 
 #endif  // THIRD_PARTY_WEBKIT_SOURCE_PLATFORM_SCHEDULER_BASE_CANCELABLE_CLOSURE_HOLDER_H_