Standardize usage of virtual/override/final in sync/

sync/internal_api/public/attachments/attachment_service_proxy_for_test.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 SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ATTACHMENT_SERVICE_PROXY_FOR_TEST_H_
 #define SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ATTACHMENT_SERVICE_PROXY_FOR_TEST_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "sync/base/sync_export.h"
 #include "sync/internal_api/public/attachments/attachment_service_proxy.h"
 
 namespace syncer {
 
 // An self-contained AttachmentServiceProxy to reduce boilerplate code in tests.
 //
 // Constructs and owns an AttachmentService suitable for use in tests.
 // NOTE: This class does not require the current thread to have a MessageLoop,
 // however all methods will effectively become no-op stubs in that case.
 class SYNC_EXPORT AttachmentServiceProxyForTest
     : public AttachmentServiceProxy {
  public:
   static AttachmentServiceProxy Create();
-  virtual ~AttachmentServiceProxyForTest();
+  ~AttachmentServiceProxyForTest() override;
 
  private:
   // A Core that owns the wrapped AttachmentService.
   class OwningCore : public AttachmentServiceProxy::Core {
    public:
     OwningCore(
         scoped_ptr<AttachmentService>,
         scoped_ptr<base::WeakPtrFactory<AttachmentService> > weak_ptr_factory);
 
    private:
-    virtual ~OwningCore();
+    ~OwningCore() override;
 
     scoped_ptr<AttachmentService> wrapped_;
     // WeakPtrFactory for wrapped_.  See Create() for why this is a scoped_ptr.
     scoped_ptr<base::WeakPtrFactory<AttachmentService> > weak_ptr_factory_;
 
     DISALLOW_COPY_AND_ASSIGN(OwningCore);
   };
 
   AttachmentServiceProxyForTest(
       const scoped_refptr<base::SequencedTaskRunner>& wrapped_task_runner,
       const scoped_refptr<Core>& core);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ATTACHMENT_SERVICE_PROXY_FOR_TEST_H_