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

Source/modules/mediastream/RTCVoidRequestImpl.h

Index: Source/modules/mediastream/RTCVoidRequestImpl.h
diff --git a/Source/modules/mediastream/RTCVoidRequestImpl.h b/Source/modules/mediastream/RTCVoidRequestImpl.h
index de20831d6d7aa9970615e34aee4dc07ef724692b..7388eca4f0f6aacf62f9ccbb00ab4be7b0a5b691 100644
--- a/Source/modules/mediastream/RTCVoidRequestImpl.h
+++ b/Source/modules/mediastream/RTCVoidRequestImpl.h
@@ -45,14 +45,14 @@ class RTCVoidRequestImpl final : public RTCVoidRequest, public ActiveDOMObject {
     WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(RTCVoidRequestImpl);
 public:
     static RTCVoidRequestImpl* create(ExecutionContext*, RTCPeerConnection*, VoidCallback*, RTCErrorCallback*);
-    virtual ~RTCVoidRequestImpl();
+    ~RTCVoidRequestImpl() override;
 
     // RTCVoidRequest
-    virtual void requestSucceeded() override;
-    virtual void requestFailed(const String& error) override;
+    void requestSucceeded() override;
+    void requestFailed(const String& error) override;
 
     // ActiveDOMObject
-    virtual void stop() override;
+    void stop() override;
 
     DECLARE_VIRTUAL_TRACE();