Move blink scheduler implementation into a component

components/scheduler/child/cancelable_closure_holder.cc

 // 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.
 
-#include "content/child/scheduler/cancelable_closure_holder.h"
+#include "components/scheduler/child/cancelable_closure_holder.h"
 
-namespace content {
+namespace scheduler {
 
 CancelableClosureHolder::CancelableClosureHolder() {
 }
 
 CancelableClosureHolder::~CancelableClosureHolder() {
 }
 
 void CancelableClosureHolder::Reset(const base::Closure& callback) {
   callback_ = callback;
   cancelable_callback_.Reset(callback_);
 }
 
 void CancelableClosureHolder::Cancel() {
   DCHECK(!callback_.is_null());
   cancelable_callback_.Reset(callback_);
 }
 
 const base::Closure& CancelableClosureHolder::callback() const {
   DCHECK(!callback_.is_null());
   return cancelable_callback_.callback();
 }
 
-}  // namespace content
+}  // namespace scheduler