[SafeBrowsing] Block dangerous unchecked downloads based on a Finch trial.

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_
+
+namespace base {
+class FilePath;
+}
+
+namespace safe_browsing {
+
+// Returns true if |file| is allowed to be downloaded without invoking
+// SafeBrowsing to verify the contents and source URL.
+bool IsUnverifiedDownloadAllowed(const base::FilePath& file);
+
+}  // namespace safe_browsing
+
+#endif  // CHROME_BROWSER_SAFE_BROWSING_UNVERIFIED_DOWNLOAD_POLICY_H_