Move blink scheduler implementation into a component

components/scheduler/child/task_queue_selector.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_TASK_QUEUE_SELECTOR_H_
-#define CONTENT_CHILD_SCHEDULER_TASK_QUEUE_SELECTOR_H_
+#ifndef COMPONENTS_SCHEDULER_CHILD_TASK_QUEUE_SELECTOR_H_
+#define COMPONENTS_SCHEDULER_CHILD_TASK_QUEUE_SELECTOR_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
-#include "content/common/content_export.h"
+#include "components/scheduler/scheduler_export.h"
 
 namespace base {
 class TaskQueue;
 namespace trace_event {
 class TracedValue;
 }  // namespace trace_event
 }  // namespace base
 
-namespace content {
+namespace scheduler {
 
 class TaskQueueSelector {
  public:
   virtual ~TaskQueueSelector() {}
 
   // Called once to register the work queues to be selected from. This function
   // is called on the main thread.
   virtual void RegisterWorkQueues(
       const std::vector<const base::TaskQueue*>& work_queues) = 0;
 
-  class CONTENT_EXPORT Observer {
+  class SCHEDULER_EXPORT Observer {
    public:
     virtual ~Observer() {}
 
     // Called when a task queue transitions from disabled to enabled.
     virtual void OnTaskQueueEnabled() = 0;
   };
 
   // Called once to set the Observer. This function is called
   // on the main thread. If |observer| is null, then no callbacks will occur.
   virtual void SetTaskQueueSelectorObserver(Observer* observer) = 0;
 
   // Called to choose the work queue from which the next task should be taken
   // and run. Return true if |out_queue| indicates the queue to service or
   // false to avoid running any task.
   //
   // This function is called on the main thread.
   virtual bool SelectWorkQueueToService(size_t* out_queue_index) = 0;
 
   // Serialize the selector state for tracing.
   virtual void AsValueInto(base::trace_event::TracedValue* state) const = 0;
 };
 
-}  // namespace content
+}  // namespace scheduler
 
-#endif  // CONTENT_CHILD_SCHEDULER_TASK_QUEUE_SELECTOR_H_
+#endif  // COMPONENTS_SCHEDULER_CHILD_TASK_QUEUE_SELECTOR_H_