Use FileTypePolicies for download danger classifications.

chrome/browser/download/download_extensions.h

-// Copyright (c) 2011 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 CHROME_BROWSER_DOWNLOAD_DOWNLOAD_EXTENSIONS_H_
-#define CHROME_BROWSER_DOWNLOAD_DOWNLOAD_EXTENSIONS_H_
-
-#include <string>
-
-#include "base/files/file_path.h"
-
-namespace download_util {
-
-enum DownloadDangerLevel {
-  // Safe. Or at least not known to be dangerous. Safe to download and open,
-  // even if the download was accidental.
-  NOT_DANGEROUS,
-
-  // Require confirmation before downloading. An additional user gesture may not
-  // be required if the download was from a familiar site and the download was
-  // initiated via a user action.
-  ALLOW_ON_USER_GESTURE,
-
-  // Always require confirmation when downloading.
-  DANGEROUS
-};
-
-// Determine the download danger level of a file.
-DownloadDangerLevel GetFileDangerLevel(const base::FilePath& path);
-
-// Returns true if the file specified by |path| is allowed to open
-// automatically.
-//
-// Not all downloads are initiated with the consent of the user. Even when the
-// user consents, the file written to disk may differ from the users'
-// expectations. I.e. a malicious website could drop a nefarious download
-// possibly by click jacking, or by serving a file that is different from what
-// the user intended to download.
-//
-// Any prompting done in order to validate a dangerous download is a speed bump
-// rather than a security measure. The user likely doesn't have the information
-// necessary to evaluate the safety of a downloaded file. In addition, downloads
-// with a danger type of ALLOW_ON_USER_GESTURE might not prompt at all. So
-// Chrome forces the user to manually open some file types by preventing them
-// from being opened automatically. See https://crbug.com/461858
-//
-// See DownloadAutoOpenHint for details on the criteria used to disallow
-// automatic opening for a file type.
-bool IsAllowedToOpenAutomatically(const base::FilePath& path);
-
-}  // namespace download_util
-
-#endif  // CHROME_BROWSER_DOWNLOAD_DOWNLOAD_EXTENSIONS_H_