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