Revert of Explicit notification and removal of lifecycle observers.

Source/core/dom/ContextLifecycleNotifier.cpp

Index: Source/core/dom/ContextLifecycleNotifier.cpp
diff --git a/Source/core/dom/ContextLifecycleNotifier.cpp b/Source/core/dom/ContextLifecycleNotifier.cpp
index 37e07f5ad4c728e9c023565afaf1ee6fdf64e061..9a585d8ed1ce1735b88d4b7506666c354e1a1a5a 100644
--- a/Source/core/dom/ContextLifecycleNotifier.cpp
+++ b/Source/core/dom/ContextLifecycleNotifier.cpp
@@ -64,12 +64,6 @@
     }
 }
 
-void ContextLifecycleNotifier::removeAndNotifyAllObservers()
-{
-    LifecycleNotifier<ExecutionContext>::removeAndNotifyAllObservers();
-    m_activeDOMObjects.clear();
-}
-
 void ContextLifecycleNotifier::notifyResumingActiveDOMObjects()
 {
     TemporaryChange<IterationType> scope(this->m_iterating, IteratingOverActiveDOMObjects);