Revert of Move remote_db_manager into the safe_browsing_db component.

components/safe_browsing_db/metadata.proto

-// Copyright 2014 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.
-
-syntax = "proto2";
-
-option optimize_for = LITE_RUNTIME;
-
-package safe_browsing;
-
-// Everything below this comment was copied from the page
-// <https://developers.google.com/safe-browsing/developers_guide_v3>,
-// section "Full Hash Metadata".
-
-// Metadata for the goog-malware-shavar list.
-message MalwarePatternType {
-  enum PATTERN_TYPE {
-    LANDING = 1;
-    DISTRIBUTION = 2;
-  }
-
-  required PATTERN_TYPE pattern_type = 1;
-}