Standardize usage of virtual/override/final in storage/

storage/browser/fileapi/file_system_file_stream_reader.h

Index: storage/browser/fileapi/file_system_file_stream_reader.h
diff --git a/storage/browser/fileapi/file_system_file_stream_reader.h b/storage/browser/fileapi/file_system_file_stream_reader.h
index 6b9273ad378eeddcffd79ac58828499924cf075e..b0a718a304e172872612a1315db2c8a140ddfa91 100644
--- a/storage/browser/fileapi/file_system_file_stream_reader.h
+++ b/storage/browser/fileapi/file_system_file_stream_reader.h
@@ -35,13 +35,13 @@ class FileSystemContext;
 class STORAGE_EXPORT_PRIVATE FileSystemFileStreamReader
     : public NON_EXPORTED_BASE(storage::FileStreamReader) {
  public:
-  virtual ~FileSystemFileStreamReader();
+  ~FileSystemFileStreamReader() override;
 
   // FileStreamReader overrides.
-  virtual int Read(net::IOBuffer* buf, int buf_len,
-                   const net::CompletionCallback& callback) override;
-  virtual int64 GetLength(
-      const net::Int64CompletionCallback& callback) override;
+  int Read(net::IOBuffer* buf,
+           int buf_len,
+           const net::CompletionCallback& callback) override;
+  int64 GetLength(const net::Int64CompletionCallback& callback) override;
 
  private:
   friend class storage::FileStreamReader;