Fix virtual/override/final usage in Source/modules/.

Source/modules/mediasource/MediaSourceRegistry.h

Index: Source/modules/mediasource/MediaSourceRegistry.h
diff --git a/Source/modules/mediasource/MediaSourceRegistry.h b/Source/modules/mediasource/MediaSourceRegistry.h
index 488a05beff03c7be1736c7fdb098f69920e317ea..2e20dc561a48f02e5fa4fe2c016b1b57771cc29a 100644
--- a/Source/modules/mediasource/MediaSourceRegistry.h
+++ b/Source/modules/mediasource/MediaSourceRegistry.h
@@ -48,9 +48,9 @@ public:
     static MediaSourceRegistry& registry();
 
     // Registers a blob URL referring to the specified media source.
-    virtual void registerURL(SecurityOrigin*, const KURL&, URLRegistrable*) override;
-    virtual void unregisterURL(const KURL&) override;
-    virtual URLRegistrable* lookup(const String&) override;
+    void registerURL(SecurityOrigin*, const KURL&, URLRegistrable*) override;
+    void unregisterURL(const KURL&) override;
+    URLRegistrable* lookup(const String&) override;
 
 private:
     MediaSourceRegistry();