Move `gn check` into the `generate_build_files` step.

components/update_client/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.
 
 source_set("update_client") {
   sources = [
     "action.cc",
     "action.h",
     "action_update.cc",
     "action_update.h",
@@ skipping 40 matching lines @@
   ]
 
   deps = [
     "//base",
     "//components/crx_file",
     "//courgette:courgette_lib",
     "//crypto",
     "//third_party/libxml",
     "//third_party/zlib:zip",
     "//net",
+    "//ui/base",
     "//url",
   ]
 }
 
 source_set("test_support") {
   testonly = true
   sources = [
     "test_configurator.cc",
     "test_configurator.h",
     "test_installer.cc",
@@ skipping 29 matching lines @@
     ":update_client",
     ":test_support",
     "//base",
     "//courgette:courgette_lib",
     "//net:test_support",
     "//testing/gtest",
     "//testing/gmock",
     "//third_party/libxml",
   ]
 }