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

Source/core/dom/NodeRareData.h

Index: Source/core/dom/NodeRareData.h
diff --git a/Source/core/dom/NodeRareData.h b/Source/core/dom/NodeRareData.h
index 120a15b6a02d422d7fbce41fcf833e9e2cf789eb..8d310c37033087e112a5adbef70253d456dfe6c6 100644
--- a/Source/core/dom/NodeRareData.h
+++ b/Source/core/dom/NodeRareData.h
@@ -249,19 +249,19 @@ public:
 
     void clearNodeLists() { m_nodeLists.clear(); }
     NodeListsNodeData* nodeLists() const { return m_nodeLists.get(); }
-    NodeListsNodeData* ensureNodeLists()
+    NodeListsNodeData& ensureNodeLists()
     {
         if (!m_nodeLists)
             m_nodeLists = NodeListsNodeData::create();
-        return m_nodeLists.get();
+        return *m_nodeLists;
     }
 
     NodeMutationObserverData* mutationObserverData() { return m_mutationObserverData.get(); }
-    NodeMutationObserverData* ensureMutationObserverData()
+    NodeMutationObserverData& ensureMutationObserverData()
     {
         if (!m_mutationObserverData)
             m_mutationObserverData = NodeMutationObserverData::create();
-        return m_mutationObserverData.get();
+        return *m_mutationObserverData;
     }
 
     unsigned connectedSubframeCount() const { return m_connectedFrameCount; }