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

Source/core/fetch/MockImageResourceClient.h

Index: Source/core/fetch/MockImageResourceClient.h
diff --git a/Source/core/fetch/MockImageResourceClient.h b/Source/core/fetch/MockImageResourceClient.h
index 1ac3b8986e1ec7e3a978965f51eeea9f5813254a..3a472ab923150bf0a608c1d6a9a4b5372028c943 100644
--- a/Source/core/fetch/MockImageResourceClient.h
+++ b/Source/core/fetch/MockImageResourceClient.h
@@ -45,13 +45,13 @@ public:
     {
     }
 
-    virtual ~MockImageResourceClient() { }
-    virtual void imageChanged(ImageResource*, const IntRect*) override
+    ~MockImageResourceClient() override {}
+    void imageChanged(ImageResource*, const IntRect*) override
     {
         m_imageChangedCount++;
     }
 
-    virtual void notifyFinished(Resource*) override
+    void notifyFinished(Resource*) override
     {
         ASSERT_FALSE(m_notifyFinishedCalled);
         m_notifyFinishedCalled = true;