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

Source/platform/credentialmanager/PlatformFederatedCredential.h

Index: Source/platform/credentialmanager/PlatformFederatedCredential.h
diff --git a/Source/platform/credentialmanager/PlatformFederatedCredential.h b/Source/platform/credentialmanager/PlatformFederatedCredential.h
index 92a51daebd18b252cad8e7e417932b6702de9631..862adaf7f1fe3c17671ee597de6f43a20d282094 100644
--- a/Source/platform/credentialmanager/PlatformFederatedCredential.h
+++ b/Source/platform/credentialmanager/PlatformFederatedCredential.h
@@ -15,11 +15,11 @@ class PLATFORM_EXPORT PlatformFederatedCredential final : public PlatformCredent
     WTF_MAKE_NONCOPYABLE(PlatformFederatedCredential);
 public:
     static PlatformFederatedCredential* create(const String& id, const KURL& federation, const String& name, const KURL& iconURL);
-    virtual ~PlatformFederatedCredential();
+    ~PlatformFederatedCredential() override;
 
     const KURL& provider() const { return m_provider; }
 
-    virtual bool isFederated() override { return true; }
+    bool isFederated() override { return true; }
 
 private:
     PlatformFederatedCredential(const String& id, const KURL& federation, const String& name, const KURL& iconURL);