WIP (Introduce WTF::NonNullPtr<T>.)

Source/core/html/HTMLMapElement.cpp

Index: Source/core/html/HTMLMapElement.cpp
diff --git a/Source/core/html/HTMLMapElement.cpp b/Source/core/html/HTMLMapElement.cpp
index bdded68b16b8589766084c0b9c8af886aec055fd..b0d0fac60c6e64cd350ae03b9abdf61a209a9264 100644
--- a/Source/core/html/HTMLMapElement.cpp
+++ b/Source/core/html/HTMLMapElement.cpp
@@ -110,13 +110,13 @@ void HTMLMapElement::parseAttribute(const QualifiedName& name, const AtomicStrin
                 return;
         }
         if (inDocument())
-            treeScope().removeImageMap(this);
+            treeScope()->removeImageMap(this);
         String mapName = value;
         if (mapName[0] == '#')
             mapName = mapName.substring(1);
         m_name = document().isHTMLDocument() ? mapName.lower() : mapName;
         if (inDocument())
-            treeScope().addImageMap(this);
+            treeScope()->addImageMap(this);
 
         return;
     }
@@ -132,14 +132,14 @@ PassRefPtr<HTMLCollection> HTMLMapElement::areas()
 Node::InsertionNotificationRequest HTMLMapElement::insertedInto(ContainerNode* insertionPoint)
 {
     if (insertionPoint->inDocument())
-        treeScope().addImageMap(this);
+        treeScope()->addImageMap(this);
     return HTMLElement::insertedInto(insertionPoint);
 }
 
 void HTMLMapElement::removedFrom(ContainerNode* insertionPoint)
 {
     if (insertionPoint->inDocument())
-        treeScope().removeImageMap(this);
+        treeScope()->removeImageMap(this);
     HTMLElement::removedFrom(insertionPoint);
 }