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

Source/core/fetch/TextResource.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef TextResource_h
 #define TextResource_h
 
 #include "core/CoreExport.h"
 #include "core/fetch/ResourcePtr.h"
 
 namespace blink {
 
 class TextResourceDecoder;
 
 class CORE_EXPORT TextResource : public Resource {
 public:
     // Returns the decoded data in text form. The data has to be available at
     // call time.
     String decodedText() const;
 
-    virtual void setEncoding(const String&) override;
-    virtual String encoding() const override;
+    void setEncoding(const String&) override;
+    String encoding() const override;
 
 protected:
     TextResource(const ResourceRequest&, Type, const String& mimeType, const String& charset);
-    virtual ~TextResource();
+    ~TextResource() override;
 
 private:
     OwnPtr<TextResourceDecoder> m_decoder;
 };
 
 }
 
 #endif // TextResource_h