Remove the enable_mac_keystone build flag.

chrome/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("//build/buildflag_header.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/compiler/pgo/pgo.gni")
 import("//build/config/features.gni")
 import("//build/config/locales.gni")
@@ skipping 480 matching lines @@
 
       public_deps = [
         "//chrome/browser/ui/cocoa/notifications:alert_notification_xpc_service",
       ]
     }
   }
 
   tweak_info_plist("chrome_app_plist") {
     info_plist = "app/app-Info.plist"
     _keystone_arg = "0"
-    if (enable_mac_keystone) {
+    if (is_chrome_branded) {
       _keystone_arg = "1"
     }
     args = [
       "--breakpad=0",
       "--keystone=$_keystone_arg",
       "--scm=1",
       "--bundle_id=$chrome_mac_bundle_id",
     ]
   }
 
@@ skipping 242 matching lines @@
 
     outputs = [
       "{{bundle_resources_dir}}/{{source_file_part}}",
     ]
 
     public_deps = [
       ":packed_resources",
       "//chrome/app_shim:app_mode_loader",
     ]
 
-    if (enable_mac_keystone) {
+    if (is_chrome_branded) {
       sources += [
         "browser/mac/keystone_promote_postflight.sh",
         "browser/mac/keystone_promote_preflight.sh",
       ]
     }
 
     if (icu_use_data_file) {
       sources += [ "$root_out_dir/icudtl.dat" ]
       public_deps += [ "//third_party/icu:icudata" ]
     }
@@ skipping 118 matching lines @@
 
   group("widevine_cdm_library") {
     if (_should_bundle_widevine) {
       deps = [
         ":widevine_cdm_library_binaries",
         ":widevine_cdm_library_manifest",
       ]
     }
   }
 
-  if (enable_mac_keystone) {
+  if (is_chrome_branded) {
     action("keystone_registration_framework") {
       script = "//chrome/tools/build/mac/copy_keystone_framework.py"
 
       framework_path = "//third_party/googlemac/Releases/Keystone/KeystoneRegistration.framework"
       output_path = "$root_out_dir/$chrome_framework_name.framework/Frameworks/"
 
       sources = [
         framework_path,
         script,
       ]
@@ skipping 687 matching lines @@
       "//chrome/app/theme/$branding_path_component/product_logo_48.png",
       "//chrome/tools/build/linux/chrome-wrapper",
       "//third_party/xdg-utils/scripts/xdg-mime",
       "//third_party/xdg-utils/scripts/xdg-settings",
     ]
     outputs = [
       "$root_out_dir/{{source_file_part}}",
     ]
   }
 }