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

Source/core/loader/EmptyClients.cpp

 /*
  * Copyright (C) 2006 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 44 matching lines @@
 
     static EditorClient* dummyEditorClient = adoptPtr(new EmptyEditorClient).leakPtr();
     pageClients.editorClient = dummyEditorClient;
 
     static SpellCheckerClient* dummySpellCheckerClient = adoptPtr(new EmptySpellCheckerClient).leakPtr();
     pageClients.spellCheckerClient = dummySpellCheckerClient;
 }
 
 class EmptyPopupMenu : public PopupMenu {
 public:
-    virtual void show(const FloatQuad&, const IntSize&, int) override { }
-    virtual void hide() override { }
-    virtual void updateFromElement() override { }
-    virtual void disconnectClient() override { }
+    void show(const FloatQuad&, const IntSize&, int) override { }
+    void hide() override { }
+    void updateFromElement() override { }
+    void disconnectClient() override { }
 };
 
 PassRefPtrWillBeRawPtr<PopupMenu> EmptyChromeClient::openPopupMenu(LocalFrame&, PopupMenuClient*)
 {
     return adoptRefWillBeNoop(new EmptyPopupMenu());
 }
 
 PassOwnPtrWillBeRawPtr<ColorChooser> EmptyChromeClient::openColorChooser(LocalFrame*, ColorChooserClient*, const Color&)
 {
     return nullptr;
@@ skipping 72 matching lines @@
 {
     return nullptr;
 }
 
 PassOwnPtr<WebApplicationCacheHost> EmptyFrameLoaderClient::createApplicationCacheHost(WebApplicationCacheHostClient*)
 {
     return nullptr;
 }
 
 } // namespace blink