Revert of Explicit notification and removal of lifecycle observers.

Source/platform/LifecycleNotifier.h

Index: Source/platform/LifecycleNotifier.h
diff --git a/Source/platform/LifecycleNotifier.h b/Source/platform/LifecycleNotifier.h
index f75d3cfccf7017b07b36210fcc9ca59186228864..57d684f009aa4b463b3ac7e83c32ac36dabbf581 100644
--- a/Source/platform/LifecycleNotifier.h
+++ b/Source/platform/LifecycleNotifier.h
@@ -64,8 +64,6 @@
     {
     }
 
-    virtual void removeAndNotifyAllObservers();
-
     Context* context() const { return m_context; }
 
     enum IterationType {
@@ -88,7 +86,7 @@
 };
 
 template<typename T>
-inline void LifecycleNotifier<T>::removeAndNotifyAllObservers()
+inline LifecycleNotifier<T>::~LifecycleNotifier()
 {
     TemporaryChange<IterationType> scope(this->m_iterating, IteratingOverAll);
     for (typename ObserverSet::iterator it = m_observers.begin(); it != m_observers.end(); it = m_observers.begin()) {
@@ -97,12 +95,6 @@
         ASSERT(observer->lifecycleContext() == m_context);
         observer->contextDestroyed();
     }
-}
-
-template<typename T>
-inline LifecycleNotifier<T>::~LifecycleNotifier()
-{
-    removeAndNotifyAllObservers();
 }
 
 template<typename T>