Move blink scheduler implementation into a component

components/scheduler/child/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 CONTENT_CHILD_SCHEDULER_CANCELABLE_CLOSURE_HOLDER_H_
-#define CONTENT_CHILD_SCHEDULER_CANCELABLE_CLOSURE_HOLDER_H_
+#ifndef COMPONENTS_SCHEDULER_CHILD_CANCELABLE_CLOSURE_HOLDER_H_
+#define COMPONENTS_SCHEDULER_CHILD_CANCELABLE_CLOSURE_HOLDER_H_
 
 #include "base/cancelable_callback.h"
 
-namespace content {
+namespace scheduler {
 
 // A CancelableClosureHolder is a CancelableCallback which resets its wrapped
 // callback with a cached closure whenever it is canceled.
 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 content
+}  // namespace scheduler
 
-#endif  // CONTENT_CHILD_SCHEDULER_CANCELABLE_CLOSURE_HOLDER_H_
+#endif  // COMPONENTS_SCHEDULER_CHILD_CANCELABLE_CLOSURE_HOLDER_H_