Add download_file_types.proto with ascii->binary conversion, as a resource.

chrome/browser/resources/safe_browsing/download_file_types.asciipb

+# Copyright 2016 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.
+
+# Placeholder for list of file extensions that the download manager
+# knows about.
+# TODO(nparker): Populate this with full list..
+version_id: 1
+light_ping_probability: 0.0
+file_type {
+  extension: "exe"
+  uma_value: 777
+  is_archive: false
+  platform_settings {
+    platform: ALL
+    danger_level: ALLOW_ON_USER_GESTURE
+    auto_open_hint: DISALLOW_AUTO_OPEN
+    ping_setting: SEND_FULL_PING
+  }
+}
+file_type {
+  extension: "zip"
+  uma_value: 888
+  is_archive: true
+  platform_settings {
+    platform: ALL
+    danger_level: NOT_DANGEROUS
+    auto_open_hint: ALLOW_AUTO_OPEN
+    ping_setting: SEND_FULL_PING  # TODO: what does this mean w/ zip?
+  }
+}
+# file_type {...}
+# file_type {...}
+# file_type {...}
+default_file_type {
+  uma_value: 19
+  is_archive: false
+  platform_settings {
+    platform: ALL
+    danger_level: ALLOW_ON_USER_GESTURE
+    auto_open_hint: DISALLOW_AUTO_OPEN
+    ping_setting: TREAT_AS_UNKNOWN
+  }
+}