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

content/test/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/config/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build_overrides/v8.gni")
 import("//media/media_options.gni")
 import("//testing/test.gni")
 import("//third_party/mojo/src/mojo/public/tools/bindings/mojom.gni")
 
 content_tests_gypi_values =
     exec_script("//build/gypi_to_gn.py",
                 [
                   rebase_path("../content_tests.gypi"),
                   "--replace=<(SHARED_INTERMEDIATE_DIR)=$root_gen_dir",
                 ],
                 "scope",
                 [ "../content_tests.gypi" ])
 
 # GYP version //content/content_tests.gypi:test_support_content
 source_set("test_support") {
   testonly = true
-  configs += [ "//build/config:precompiled_headers" ]
+
+  configs += [
+    "//build/config:precompiled_headers",
+    "//v8:external_startup_data",
+  ]
+
   public_deps = [
     "//content/public/app:both",
     "//content/public/browser",
     "//content/public/common",
   ]
   deps = [
     "//cc/blink",
     "//net:test_support",
     "//skia",
     "//storage/common",
@@ skipping 165 matching lines @@
     "//skia",
     "//testing/gtest",
     "//ui/accessibility:ax_gen",
   ]
 
   if (is_android) {
     deps += [ "//content/public/app:both" ]
   } else {
     deps += [ "//content/public/browser" ]
   }
+
+  configs += [ "//v8:external_startup_data" ]
 }
 
 mojom("content_test_mojo_bindings") {
   sources = [
     "../public/test/test_mojo_service.mojom",
   ]
 }
 
 mojom("web_ui_test_mojo_bindings") {
   sources = [
@@ skipping 572 matching lines @@
       "//testing/gtest",
       "//third_party/WebKit/public:blink",
       "//ui/base",
       "//ui/gfx",
       "//ui/gfx/geometry",
       "//ui/gl",
       "//ui/gl:test_support",
     ]
   }
 }