Standardize usage of virtual/override/final in sync/

sync/internal_api/public/attachments/attachment_service_impl.h

Index: sync/internal_api/public/attachments/attachment_service_impl.h
diff --git a/sync/internal_api/public/attachments/attachment_service_impl.h b/sync/internal_api/public/attachments/attachment_service_impl.h
index 89cc333c7b25caab8000ce42b11aef5af20651ff..ae2e8b3539c134c0de1cf7cc9b5f1e4549c79f80 100644
--- a/sync/internal_api/public/attachments/attachment_service_impl.h
+++ b/sync/internal_api/public/attachments/attachment_service_impl.h
@@ -53,23 +53,21 @@ class SYNC_EXPORT AttachmentServiceImpl
                         Delegate* delegate,
                         const base::TimeDelta& initial_backoff_delay,
                         const base::TimeDelta& max_backoff_delay);
-  virtual ~AttachmentServiceImpl();
+  ~AttachmentServiceImpl() override;
 
   // Create an AttachmentServiceImpl suitable for use in tests.
   static scoped_ptr<syncer::AttachmentService> CreateForTest();
 
   // AttachmentService implementation.
-  virtual AttachmentStore* GetStore() override;
-  virtual void GetOrDownloadAttachments(
-      const AttachmentIdList& attachment_ids,
-      const GetOrDownloadCallback& callback) override;
-  virtual void DropAttachments(const AttachmentIdList& attachment_ids,
-                               const DropCallback& callback) override;
-  virtual void UploadAttachments(
-      const AttachmentIdSet& attachment_ids) override;
+  AttachmentStore* GetStore() override;
+  void GetOrDownloadAttachments(const AttachmentIdList& attachment_ids,
+                                const GetOrDownloadCallback& callback) override;
+  void DropAttachments(const AttachmentIdList& attachment_ids,
+                       const DropCallback& callback) override;
+  void UploadAttachments(const AttachmentIdSet& attachment_ids) override;
 
   // NetworkChangeObserver implementation.
-  virtual void OnNetworkChanged(
+  void OnNetworkChanged(
       net::NetworkChangeNotifier::ConnectionType type) override;
 
   // Use |timer| in the underlying TaskQueue.