Remove PageVisibilityObserver contextDestroyed() notifications.

third_party/WebKit/Source/modules/wake_lock/ScreenWakeLock.cpp

 // 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.
 
 #include "modules/wake_lock/ScreenWakeLock.h"
 
 #include "core/dom/Document.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Screen.h"
 #include "core/page/PageVisibilityState.h"
@@ skipping 37 matching lines @@
 }
 
 void ScreenWakeLock::pageVisibilityChanged() {
   notifyService();
 }
 
 void ScreenWakeLock::contextDestroyed(ExecutionContext*) {
   setKeepAwake(false);
 }
 
-void ScreenWakeLock::contextDestroyed(Page*) {}
-
 DEFINE_TRACE(ScreenWakeLock) {
   Supplement<LocalFrame>::trace(visitor);
   PageVisibilityObserver::trace(visitor);
   ContextLifecycleObserver::trace(visitor);
 }
 
 ScreenWakeLock::ScreenWakeLock(LocalFrame& frame)
     : Supplement<LocalFrame>(frame),
       ContextLifecycleObserver(frame.document()),
       PageVisibilityObserver(frame.page()),
@@ skipping 21 matching lines @@
   if (!m_service)
     return;
 
   if (m_keepAwake && page() && page()->isPageVisible())
     m_service->RequestWakeLock();
   else
     m_service->CancelWakeLock();
 }
 
 }  // namespace blink