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

Source/core/dom/ContextLifecycleObserver.cpp

 /*
  * Copyright (C) 2008 Apple 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 COMPUTER, 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 COMPUTER, 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/dom/ContextLifecycleObserver.h"
 
-#include "core/dom/ContextLifecycleNotifier.h"
 #include "core/dom/ExecutionContext.h"
 
 namespace blink {
 
-template<> void observeContext(ExecutionContext* context, LifecycleObserver<ExecutionContext>* observer)
+template<> void observerContext(ExecutionContext* context, LifecycleObserver<ExecutionContext>* observer)
 {
-    context->addObserver(observer);
+    context->wasObservedBy(observer);
 }
 
-template<> void unobserveContext(ExecutionContext* context, LifecycleObserver<ExecutionContext>* observer)
+template<> void unobserverContext(ExecutionContext* context, LifecycleObserver<ExecutionContext>* observer)
 {
-    context->removeObserver(observer);
+    context->wasUnobservedBy(observer);
 }
 
 ContextLifecycleObserver::ContextLifecycleObserver(ExecutionContext* executionContext, Type type)
     : LifecycleObserver<ExecutionContext>(executionContext, type)
 {
 }
 
 ContextLifecycleObserver::~ContextLifecycleObserver()
 {
 }
 
 } // namespace blink