Remove unnecessary add/removeObserver lifetime notifier indirections.

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 7a6fbde93ed8cc165888963ea39b93e2914e49a6..72cde3cdadfc4e0fddd9313df7060539f81f84ae 100644
--- a/Source/core/dom/DocumentLifecycleNotifier.cpp
+++ b/Source/core/dom/DocumentLifecycleNotifier.cpp
@@ -36,16 +36,6 @@ DocumentLifecycleNotifier::DocumentLifecycleNotifier(Document* document)
 {
 }
 
-void DocumentLifecycleNotifier::addObserver(DocumentLifecycleObserver* observer)
-{
-    LifecycleNotifier<Document, DocumentLifecycleObserver>::addObserver(observer);
-}
-
-void DocumentLifecycleNotifier::removeObserver(DocumentLifecycleObserver* observer)
-{
-    LifecycleNotifier<Document, DocumentLifecycleObserver>::removeObserver(observer);
-}
-
 void DocumentLifecycleNotifier::notifyDocumentWasDetached()
 {
     TemporaryChange<IterationType> scope(m_iterating, IteratingOverAll);