[SafeBrowsing] Alternate extensions should also be subject to block list.

chrome/browser/safe_browsing/unverified_download_policy.h

 // Copyright 2015 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_SAFE_BROWSING_UNVERIFIED_DOWNLOAD_POLICY_H_
 #define CHROME_BROWSER_SAFE_BROWSING_UNVERIFIED_DOWNLOAD_POLICY_H_
 
+#include <vector>
+
 #include "base/callback_forward.h"
+#include "base/files/file_path.h"
 
 class GURL;
 
-namespace base {
-class FilePath;
-}
-
 namespace safe_browsing {
 
 enum class UnverifiedDownloadPolicy { ALLOWED, DISALLOWED };
 
 using UnverifiedDownloadCheckCompletionCallback =
     base::Callback<void(UnverifiedDownloadPolicy)>;
 
 // Invokes |callback| on the current thread with the effective download policy
-// for an unverified download of |file| by |requestor|.
+// for an unverified download of |file| by |requestor|. If it is possible for
+// the file to be downloaded with alternate file extensions, they should be
+// specified in |alternate_extensions|.
 void CheckUnverifiedDownloadPolicy(
     const GURL& requestor,
     const base::FilePath& file,
+    const std::vector<base::FilePath::StringType>& alternate_extensions,
     const UnverifiedDownloadCheckCompletionCallback& callback);
 
 }  // namespace safe_browsing
 
 #endif  // CHROME_BROWSER_SAFE_BROWSING_UNVERIFIED_DOWNLOAD_POLICY_H_