Add a signal to the scheduler that a navigation is expected

components/scheduler/renderer/renderer_web_scheduler_impl.h

 // Copyright 2015 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 COMPONENTS_SCHEDULER_RENDERER_RENDERER_WEB_SCHEDULER_IMPL_H_
 #define COMPONENTS_SCHEDULER_RENDERER_RENDERER_WEB_SCHEDULER_IMPL_H_
 
 #include "components/scheduler/child/web_scheduler_impl.h"
 
 namespace scheduler {
 
 class RendererScheduler;
 
 class SCHEDULER_EXPORT RendererWebSchedulerImpl : public WebSchedulerImpl {
  public:
   explicit RendererWebSchedulerImpl(RendererScheduler* child_scheduler);
 
   ~RendererWebSchedulerImpl() override;
 
   // blink::WebScheduler implementation:
-  virtual void suspendTimerQueue();
-  virtual void resumeTimerQueue();
+  void suspendTimerQueue() override;
+  void resumeTimerQueue() override;
+  void onNavigationExpected() override;
+  void onNavigationCanceled() override;
 
  private:
   RendererScheduler* renderer_scheduler_;  // NOT OWNED
 };
 
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_RENDERER_RENDERER_WEB_SCHEDULER_IMPL_H_