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

Source/platform/credentialmanager/PlatformPasswordCredential.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef PlatformPasswordCredential_h
 #define PlatformPasswordCredential_h
 
 #include "platform/credentialmanager/PlatformCredential.h"
 #include "platform/heap/Handle.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class PLATFORM_EXPORT PlatformPasswordCredential final : public PlatformCredential {
     WTF_MAKE_NONCOPYABLE(PlatformPasswordCredential);
 public:
     static PlatformPasswordCredential* create(const String& id, const String& password, const String& name, const KURL& iconURL);
-    virtual ~PlatformPasswordCredential();
+    ~PlatformPasswordCredential() override;
 
     const String& password() const { return m_password; }
 
-    virtual bool isPassword() override { return true; }
+    bool isPassword() override { return true; }
 
 private:
     PlatformPasswordCredential(const String& id, const String& password, const String& name, const KURL& iconURL);
 
     String m_password;
 };
 
 } // namespace blink
 
 #endif // PlatformPasswordCredential_h