[Sync] Move //sync to //components/sync.

sync/protocol/BUILD.gn

-# 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.
-
-import("//third_party/protobuf/proto_library.gni")
-import("protocol_sources.gni")
-
-# This must be a component for the dependency structure we have now, but the
-# proto_library generates a source set. Link those into a component.
-component("protocol") {
-  public_deps = [
-    ":protocol_internal",
-  ]
-}
-
-proto_library("protocol_internal") {
-  visibility = [ ":protocol" ]
-
-  sources = sync_protocol_sources
-
-  cc_generator_options = "dllexport_decl=SYNC_PROTO_EXPORT:"
-  cc_include = "sync/protocol/sync_proto_export.h"
-  component_build_force_source_set = true
-
-  defines = [ "SYNC_PROTO_IMPLEMENTATION" ]
-
-  extra_configs = [ "//build/config/compiler:wexit_time_destructors" ]
-}