Remove PageVisibilityObserver contextDestroyed() notifications.

third_party/WebKit/Source/modules/screen_orientation/ScreenOrientationControllerImpl.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/screen_orientation/ScreenOrientationControllerImpl.h"
 
 #include "core/dom/Document.h"
 #include "core/events/Event.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
@@ skipping 197 matching lines @@
 bool ScreenOrientationControllerImpl::hasLastData() {
   return true;
 }
 
 void ScreenOrientationControllerImpl::contextDestroyed(ExecutionContext*) {
   stopUpdating();
   m_client = nullptr;
   m_activeLock = false;
 }
 
-void ScreenOrientationControllerImpl::contextDestroyed(Page*) {}
-
 void ScreenOrientationControllerImpl::notifyDispatcher() {
   if (m_orientation && page()->isPageVisible())
     startUpdating();
   else
     stopUpdating();
 }
 
 DEFINE_TRACE(ScreenOrientationControllerImpl) {
   visitor->trace(m_orientation);
   ContextLifecycleObserver::trace(visitor);
   Supplement<LocalFrame>::trace(visitor);
   PlatformEventController::trace(visitor);
 }
 
 }  // namespace blink