Reading List create protobuf store

ios/chrome/browser/reading_list/proto/BUILD.gn

+# 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.
+
+import("//third_party/protobuf/proto_library.gni")
+
+config("sync_proto_header") {
+  include_dirs = [ "$root_gen_dir/components/sync/protocol" ]
+}
+
+proto_library("proto") {
+  sources = [
+    "reading_list.proto",
+  ]
+  deps = [
+    "//components/sync/protocol",
+  ]
+  proto_path = [ "//components/sync/protocol" ]
+  public_configs = [ ":sync_proto_header" ]
+}