Remove PageVisibilityObserver contextDestroyed() notifications.

third_party/WebKit/Source/modules/battery/BatteryManager.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 BatteryManager_h
 #define BatteryManager_h
 
 #include "bindings/core/v8/ActiveScriptWrappable.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptPromiseProperty.h"
@@ skipping 41 matching lines @@
   // Inherited from PlatformEventController.
   void didUpdateData() override;
   void registerWithDispatcher() override;
   void unregisterWithDispatcher() override;
   bool hasLastData() override;
 
   // SuspendableObject implementation.
   void suspend() override;
   void resume() override;
   void contextDestroyed(ExecutionContext*) override;
-  void contextDestroyed(Page*) override;
 
   // ScriptWrappable implementation.
   bool hasPendingActivity() const final;
 
   DECLARE_VIRTUAL_TRACE();
 
  private:
   explicit BatteryManager(ExecutionContext*);
 
   using BatteryProperty = ScriptPromiseProperty<Member<BatteryManager>,
                                                 Member<BatteryManager>,
                                                 Member<DOMException>>;
   Member<BatteryProperty> m_batteryProperty;
   BatteryStatus m_batteryStatus;
 };
 
 }  // namespace blink
 
 #endif  // BatteryManager_h