Fix virtual/override/final usage in Source/core/{fetch,loader,streams,xmlhttprequest}/.

Source/core/streams/Stream.h

Index: Source/core/streams/Stream.h
diff --git a/Source/core/streams/Stream.h b/Source/core/streams/Stream.h
index 79b7e465ecef6d60993e77edd346f3c74d62eeb1..1e83727b66488e5902673299228b9b79da3d7ba2 100644
--- a/Source/core/streams/Stream.h
+++ b/Source/core/streams/Stream.h
@@ -53,7 +53,7 @@ public:
         return stream;
     }
 
-    virtual ~Stream();
+    ~Stream() override;
 
     // Returns the internal URL referring to this stream.
     const KURL& url() const { return m_internalURL; }
@@ -80,9 +80,9 @@ public:
     // Implementation of ActiveDOMObject.
     //
     // FIXME: Implement suspend() and resume() when necessary.
-    virtual void suspend() override;
-    virtual void resume() override;
-    virtual void stop() override;
+    void suspend() override;
+    void resume() override;
+    void stop() override;
 
     DECLARE_VIRTUAL_TRACE();