Revert r189385 "Remove LifecycleContext" and r189391, r189530, r189456 that block it

Source/core/frame/DOMWindowLifecycleObserver.cpp

 /*
  * Copyright (C) 2013 Google Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 
 #include "config.h"
 #include "core/frame/DOMWindowLifecycleObserver.h"
 
-#include "core/frame/DOMWindowLifecycleNotifier.h"
 #include "core/frame/LocalDOMWindow.h"
 
 namespace blink {
 
-template<> void observeContext(LocalDOMWindow* context, LifecycleObserver<LocalDOMWindow>* observer)
+template<> void observerContext(LocalDOMWindow* context, LifecycleObserver<LocalDOMWindow>* observer)
 {
-    context->addObserver(observer);
+    context->wasObservedBy(observer);
 }
 
-template<> void unobserveContext(LocalDOMWindow* context, LifecycleObserver<LocalDOMWindow>* observer)
+template<> void unobserverContext(LocalDOMWindow* context, LifecycleObserver<LocalDOMWindow>* observer)
 {
-    context->removeObserver(observer);
+    context->wasUnobservedBy(observer);
 }
 
 DOMWindowLifecycleObserver::DOMWindowLifecycleObserver(LocalDOMWindow* window)
     : LifecycleObserver<LocalDOMWindow>(window, DOMWindowLifecycleObserverType)
 {
 }
 
 DOMWindowLifecycleObserver::~DOMWindowLifecycleObserver()
 {
 }
 
 } // namespace blink