Remove PageVisibilityObserver contextDestroyed() notifications.

third_party/WebKit/Source/modules/battery/BatteryManager.cpp

 // 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 "modules/battery/BatteryManager.h"
 
 #include "core/dom/DOMException.h"
 #include "core/dom/Document.h"
 #include "core/events/Event.h"
 #include "modules/battery/BatteryDispatcher.h"
@@ skipping 93 matching lines @@
   m_hasEventListener = true;
   startUpdating();
 }
 
 void BatteryManager::contextDestroyed(ExecutionContext*) {
   m_hasEventListener = false;
   m_batteryProperty = nullptr;
   stopUpdating();
 }
 
-void BatteryManager::contextDestroyed(Page*) {}
-
 bool BatteryManager::hasPendingActivity() const {
   // Prevent V8 from garbage collecting the wrapper object if there are
   // event listeners attached to it.
   return getExecutionContext() && hasEventListeners();
 }
 
 DEFINE_TRACE(BatteryManager) {
   visitor->trace(m_batteryProperty);
   PlatformEventController::trace(visitor);
   EventTargetWithInlineData::trace(visitor);
   SuspendableObject::trace(visitor);
 }
 
 }  // namespace blink