Remove "extra checks"

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.
 
 # Because standalone V8 builds are not supported, assume this is part of a
 # Chromium build.
 import("//build/module_args/v8.gni")
 
 # TODO(jochen): These will need to be user-settable to support standalone V8
 # builds.
 v8_deprecation_warnings = false
 v8_enable_disassembler = false
 v8_enable_gdbjit = false
 v8_enable_handle_zapping = true
 v8_enable_i18n_support = true
 v8_enable_verify_heap = false
 v8_interpreted_regexp = false
 v8_object_print = false
 v8_postmortem_support = false
 v8_use_snapshot = true
-v8_enable_extra_checks = is_debug
 v8_target_arch = cpu_arch
 v8_random_seed = "314159265"
 
 ###############################################################################
 # Configurations
 #
 config("internal_config") {
   visibility = [ ":*" ]  # Only targets in this file can depend on this.
 
   include_dirs = [ "." ]
@@ skipping 43 matching lines @@
   }
   if (v8_interpreted_regexp == true) {
     defines += [ "V8_INTERPRETED_REGEXP" ]
   }
   if (v8_deprecation_warnings == true) {
     defines += [ "V8_DEPRECATION_WARNINGS" ]
   }
   if (v8_enable_i18n_support == true) {
     defines += [ "V8_I18N_SUPPORT" ]
   }
-  if (v8_enable_extra_checks == true) {
-    defines += [ "ENABLE_EXTRA_CHECKS" ]
-  }
   if (v8_enable_handle_zapping == true) {
     defines += [ "ENABLE_HANDLE_ZAPPING" ]
   }
   if (v8_use_external_startup_data == true) {
     defines += [ "V8_USE_EXTERNAL_STARTUP_DATA" ]
   }
 }
 
 config("toolchain") {
   visibility = [ ":*" ]  # Only targets in this file can depend on this.
@@ skipping 1423 matching lines @@
       assert(!v8_use_external_startup_data)
       deps = [
         ":v8_base",
         ":v8_nosnapshot",
       ]
     }
 
     direct_dependent_configs = [ ":external_config" ]
   }
 }