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

Source/core/dom/DocumentLifecycleNotifier.cpp

Index: Source/core/dom/DocumentLifecycleNotifier.cpp
diff --git a/Source/core/dom/DocumentLifecycleNotifier.cpp b/Source/core/dom/DocumentLifecycleNotifier.cpp
index 39a4c2d47d9d424537556e26fefb62763bf9358c..1fdd210fed133f9f43060b407ec2d03bf9b3f9ee 100644
--- a/Source/core/dom/DocumentLifecycleNotifier.cpp
+++ b/Source/core/dom/DocumentLifecycleNotifier.cpp
@@ -27,7 +27,6 @@
 #include "config.h"
 #include "core/dom/DocumentLifecycleNotifier.h"
 
-#include "core/dom/DocumentLifecycleObserver.h"
 #include "wtf/Assertions.h"
 
 namespace blink {
@@ -57,20 +56,4 @@ void DocumentLifecycleNotifier::removeObserver(DocumentLifecycleNotifier::Observ
     LifecycleNotifier<Document>::removeObserver(observer);
 }
 
-void DocumentLifecycleNotifier::notifyDocumentWasDetached()
-{
-    TemporaryChange<IterationType> scope(m_iterating, IteratingOverDocumentObservers);
-    for (DocumentLifecycleObserver* observer : m_documentObservers)
-        observer->documentWasDetached();
-}
-
-#if !ENABLE(OILPAN)
-void DocumentLifecycleNotifier::notifyDocumentWasDisposed()
-{
-    TemporaryChange<IterationType> scope(m_iterating, IteratingOverDocumentObservers);
-    for (DocumentLifecycleObserver* observer : m_documentObservers)
-        observer->documentWasDisposed();
-}
-#endif
-
 } // namespace blink