Have NodeRareData's ensureNodeLists() / ensureMutationObserverData() return a reference

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 3fcb425f2b53b0a2840dfb66ec1af7d6a0889287..f6cc3645a165baf997cde2a0e685a2f3459cda15 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -4262,7 +4262,7 @@ bool Document::hasSVGRootNode() const
 
 PassRefPtr<HTMLCollection> Document::ensureCachedCollection(CollectionType type)
 {
-    return ensureRareData().ensureNodeLists()->addCacheWithAtomicName<HTMLCollection>(this, type);
+    return ensureRareData().ensureNodeLists().addCacheWithAtomicName<HTMLCollection>(this, type);
 }
 
 PassRefPtr<HTMLCollection> Document::images()
@@ -4314,17 +4314,17 @@ PassRefPtr<HTMLCollection> Document::allForBinding()
 
 PassRefPtr<HTMLCollection> Document::all()
 {
-    return ensureRareData().ensureNodeLists()->addCacheWithAtomicName<HTMLAllCollection>(this, DocAll);
+    return ensureRareData().ensureNodeLists().addCacheWithAtomicName<HTMLAllCollection>(this, DocAll);
 }
 
 PassRefPtr<HTMLCollection> Document::windowNamedItems(const AtomicString& name)
 {
-    return ensureRareData().ensureNodeLists()->addCacheWithAtomicName<HTMLNameCollection>(this, WindowNamedItems, name);
+    return ensureRareData().ensureNodeLists().addCacheWithAtomicName<HTMLNameCollection>(this, WindowNamedItems, name);
 }
 
 PassRefPtr<HTMLCollection> Document::documentNamedItems(const AtomicString& name)
 {
-    return ensureRareData().ensureNodeLists()->addCacheWithAtomicName<HTMLNameCollection>(this, DocumentNamedItems, name);
+    return ensureRareData().ensureNodeLists().addCacheWithAtomicName<HTMLNameCollection>(this, DocumentNamedItems, name);
 }
 
 void Document::finishedParsing()