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

Source/platform/heap/glue/MessageLoopInterruptor.h

Index: Source/platform/heap/glue/MessageLoopInterruptor.h
diff --git a/Source/platform/heap/glue/MessageLoopInterruptor.h b/Source/platform/heap/glue/MessageLoopInterruptor.h
index 721efce284429d4c6d55babec561c06a56ec64b5..5a37c722acdec049bb8c745087015ae2b6acd3b4 100644
--- a/Source/platform/heap/glue/MessageLoopInterruptor.h
+++ b/Source/platform/heap/glue/MessageLoopInterruptor.h
@@ -41,7 +41,7 @@ class MessageLoopInterruptor : public ThreadState::Interruptor {
 public:
     explicit MessageLoopInterruptor(WebThread* thread) : m_thread(thread) { }
 
-    virtual void requestInterrupt() override
+    void requestInterrupt() override
     {
         // GCTask has an empty run() method. Its only purpose is to guarantee
         // that MessageLoop will have a task to process which will result
@@ -54,7 +54,7 @@ private:
     public:
         virtual ~GCTask() { }
 
-        virtual void run() override
+        void run() override
         {
             // Don't do anything here because we don't know if this is
             // a nested event loop or not. PendingGCRunner::didProcessTask