Standardize usage of virtual/override/final in sync/

sync/internal_api/public/attachments/on_disk_attachment_store.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_ON_DISK_ATTACHMENT_STORE_H_
 #define SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ON_DISK_ATTACHMENT_STORE_H_
 
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
 #include "base/threading/non_thread_safe.h"
@@ skipping 13 matching lines @@
 namespace syncer {
 
 // On-disk implementation of AttachmentStore. Stores attachments in leveldb
 // database in |path| directory.
 class SYNC_EXPORT OnDiskAttachmentStore : public AttachmentStoreBase,
                                           public base::NonThreadSafe {
  public:
   // Constructs attachment store.
   OnDiskAttachmentStore(
       const scoped_refptr<base::SequencedTaskRunner>& callback_task_runner);
-  virtual ~OnDiskAttachmentStore();
+  ~OnDiskAttachmentStore() override;
 
   // AttachmentStoreBase implementation.
   // Load opens database, creating it if needed. In the future upgrade code will
   // be invoked from Load as well. If loading fails it posts |callback| with
   // UNSPECIFIED_ERROR.
-  virtual void Read(const AttachmentIdList& ids,
-                    const ReadCallback& callback) override;
-  virtual void Write(const AttachmentList& attachments,
-                     const WriteCallback& callback) override;
-  virtual void Drop(const AttachmentIdList& ids,
-                    const DropCallback& callback) override;
+  void Read(const AttachmentIdList& ids, const ReadCallback& callback) override;
+  void Write(const AttachmentList& attachments,
+             const WriteCallback& callback) override;
+  void Drop(const AttachmentIdList& ids, const DropCallback& callback) override;
 
   // Opens leveldb database at |path|. It will create directory and database if
   // it doesn't exist.
   Result OpenOrCreate(const base::FilePath& path);
 
  private:
   std::string CreateDataKeyFromAttachmentId(const AttachmentId& attachment_id);
 
   scoped_refptr<base::SequencedTaskRunner> callback_task_runner_;
   scoped_ptr<leveldb::DB> db_;
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_ATTACHMENTS_ON_DISK_ATTACHMENT_STORE_H_