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

Source/core/dom/DocumentLifecycleNotifier.h

Index: Source/core/dom/DocumentLifecycleNotifier.h
diff --git a/Source/core/dom/DocumentLifecycleNotifier.h b/Source/core/dom/DocumentLifecycleNotifier.h
index 229002a212b63bd1db64590e5c99ab4877f5d95b..abb78e0c11da6d67165b0e4ba70da3714e8acb50 100644
--- a/Source/core/dom/DocumentLifecycleNotifier.h
+++ b/Source/core/dom/DocumentLifecycleNotifier.h
@@ -26,18 +26,17 @@
 #ifndef DocumentLifecycleNotifier_h
 #define DocumentLifecycleNotifier_h
 
-#include "platform/LifecycleNotifier.h"
-#include "wtf/HashSet.h"
+#include "core/dom/Document.h"
+#include "core/dom/DocumentLifecycleObserver.h"
 #include "wtf/PassOwnPtr.h"
 #include "wtf/TemporaryChange.h"
 
 namespace blink {
 
-class Document;
-class DocumentLifecycleObserver;
-
 class DocumentLifecycleNotifier : public LifecycleNotifier<Document> {
 public:
+    static PassOwnPtr<DocumentLifecycleNotifier> create(Document*);
+
     void notifyDocumentWasDetached();
 #if !ENABLE(OILPAN)
     void notifyDocumentWasDisposed();
@@ -46,14 +45,34 @@ public:
     virtual void addObserver(Observer*) override final;
     virtual void removeObserver(Observer*) override final;
 
-protected:
+private:
     explicit DocumentLifecycleNotifier(Document*);
 
-private:
     using DocumentObserverSet = HashSet<DocumentLifecycleObserver*>;
     DocumentObserverSet m_documentObservers;
 };
 
+inline PassOwnPtr<DocumentLifecycleNotifier> DocumentLifecycleNotifier::create(Document* document)
+{
+    return adoptPtr(new DocumentLifecycleNotifier(document));
+}
+
+inline void DocumentLifecycleNotifier::notifyDocumentWasDetached()
+{
+    TemporaryChange<IterationType> scope(this->m_iterating, IteratingOverDocumentObservers);
+    for (DocumentLifecycleObserver* observer : m_documentObservers)
+        observer->documentWasDetached();
+}
+
+#if !ENABLE(OILPAN)
+inline void DocumentLifecycleNotifier::notifyDocumentWasDisposed()
+{
+    TemporaryChange<IterationType> scope(this->m_iterating, IteratingOverDocumentObservers);
+    for (DocumentLifecycleObserver* observer : m_documentObservers)
+        observer->documentWasDisposed();
+}
+#endif
+
 } // namespace blink
 
 #endif // DocumentLifecycleNotifier_h