Revert of Add a buildflag to use the handle verifier in a per module mode.

base/win/BUILD.gn

-# Copyright (c) 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("//build/buildflag_header.gni")
-
-declare_args() {
-  # Indicates if the handle verifier should operate in a single module mode. By
-  # default a single instance gets shared by all the modules.
-  single_module_mode_handle_verifier = false
-}
-
-# Ensure that the handle verifier is always used in a single module mode for the
-# component builds.
-if (is_component_build) {
-  single_module_mode_handle_verifier = true
-}
-
-buildflag_header("base_win_features") {
-  header = "base_features.h"
-  header_dir = "base/win"
-  flags = [ "SINGLE_MODULE_MODE_HANDLE_VERIFIER=single_module_mode_handle_verifier" ]
-}