Update fetch / loader classes to use OVERRIDE / FINAL when needed

Source/core/fetch/DocumentResourceReference.h

Index: Source/core/fetch/DocumentResourceReference.h
diff --git a/Source/core/fetch/DocumentResourceReference.h b/Source/core/fetch/DocumentResourceReference.h
index 9e8433583f9259b1a621e4d4ec13cdad96901e82..60f7448818894894046869ef19cf76f218b75524 100644
--- a/Source/core/fetch/DocumentResourceReference.h
+++ b/Source/core/fetch/DocumentResourceReference.h
@@ -31,7 +31,7 @@
 
 namespace WebCore {
 
-class DocumentResourceReference : public DocumentResourceClient {
+class DocumentResourceReference FINAL : public DocumentResourceClient {
 public:
     DocumentResourceReference(DocumentResource* document) : m_document(document) { m_document->addClient(this); }
     virtual ~DocumentResourceReference() { m_document->removeClient(this); }