Move v8_use_external_startup_data out of //build/config:feature_flags.

build/config/BUILD.gn

 # Copyright (c) 2013 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/config/allocator.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/ui.gni")
-import("//build_overrides/v8.gni")
 import("//build/toolchain/goma.gni")
 
 declare_args() {
   # When set (the default) enables C++ iterator debugging in debug builds.
   # Iterator debugging is always off in release builds (technically, this flag
   # affects the "debug" config, which is always available but applied by
   # default only in debug builds).
   #
   # Iterator debugging is generally useful for catching bugs. But it can
   # introduce extra locking to check the state of an iterator against the state
@@ skipping 214 matching lines @@
   }
   if (enable_topchrome_md) {
     defines += [ "ENABLE_TOPCHROME_MD=1" ]
   }
   if (proprietary_codecs) {
     defines += [ "USE_PROPRIETARY_CODECS" ]
   }
   if (enable_hangout_services_extension) {
     defines += [ "ENABLE_HANGOUT_SERVICES_EXTENSION=1" ]
   }
-  if (v8_use_external_startup_data) {
-    defines += [ "V8_USE_EXTERNAL_STARTUP_DATA" ]
-  }
   if (enable_background) {
     defines += [ "ENABLE_BACKGROUND=1" ]
   }
   if (enable_pre_sync_backup) {
     defines += [ "ENABLE_PRE_SYNC_BACKUP" ]
   }
   if (enable_video_hole) {
     defines += [ "VIDEO_HOLE=1" ]
   }
   if (safe_browsing_mode == 1) {
@@ skipping 184 matching lines @@
     # This error doesn't happen every time. In VS2013, it seems if the .pch
     # file doesn't exist, no error will be generated (probably MS tested this
     # case but forgot the other one?). To reproduce this error, do a build,
     # then delete the precompile.c.obj file, then build again.
     cflags_c = [ "/wd4206" ]
   } else if (is_mac && !is_official_build && !use_goma) {
     precompiled_header = "build/precompile.h"
     precompiled_source = "//build/precompile.h"
   }
 }