Standardize usage of virtual/override/final in sync/

sync/internal_api/public/attachments/attachment_store_handle.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_STORE_HANDLE_H_
 #define SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ATTACHMENT_STORE_HANDLE_H_
 
 #include <map>
 
 #include "base/memory/ref_counted.h"
@@ skipping 23 matching lines @@
 // AttachmentStoreHandle is not thread safe, it should only be accessed from
 // model thread.
 class SYNC_EXPORT AttachmentStoreHandle : public AttachmentStore,
                                           public base::NonThreadSafe {
  public:
   AttachmentStoreHandle(
       scoped_ptr<AttachmentStoreBase> backend,
       const scoped_refptr<base::SequencedTaskRunner>& backend_task_runner);
 
   // AttachmentStore implementation.
-  virtual void Read(const AttachmentIdList& id,
-                    const ReadCallback& callback) override;
-  virtual void Write(const AttachmentList& attachments,
-                     const WriteCallback& callback) override;
-  virtual void Drop(const AttachmentIdList& id,
-                    const DropCallback& callback) override;
+  void Read(const AttachmentIdList& id, const ReadCallback& callback) override;
+  void Write(const AttachmentList& attachments,
+             const WriteCallback& callback) override;
+  void Drop(const AttachmentIdList& id, const DropCallback& callback) override;
 
  private:
-  virtual ~AttachmentStoreHandle();
+  ~AttachmentStoreHandle() override;
 
   // AttachmentStoreHandle controls backend's lifetime. It is safe for
   // AttachmentStoreHandle to bind backend through base::Unretained for posts.
   // Backend is deleted on backend_task_runner, after that backend_ pointer is
   // invalid.
   scoped_ptr<AttachmentStoreBase> backend_;
   scoped_refptr<base::SequencedTaskRunner> backend_task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(AttachmentStoreHandle);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ATTACHMENT_STORE_HANDLE_H_