Allow generation of a chromium outdirs when enable_extensions=false

extensions/browser/value_store/BUILD.gn

 # Copyright 2016 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("//extensions/features/features.gni")
+
+assert(enable_extensions,
+       "Cannot depend on extensions because enable_extensions=false.")
+
 source_set("value_store") {
   sources = [
     "lazy_leveldb.cc",
     "lazy_leveldb.h",
     "legacy_value_store_factory.cc",
     "legacy_value_store_factory.h",
     "leveldb_scoped_database.cc",
     "leveldb_scoped_database.h",
     "leveldb_value_store.cc",
     "leveldb_value_store.h",
     "test_value_store_factory.cc",
     "test_value_store_factory.h",
     "testing_value_store.cc",
     "testing_value_store.h",
     "value_store.cc",
     "value_store.h",
     "value_store_change.cc",
     "value_store_change.h",
     "value_store_factory.h",
     "value_store_factory_impl.cc",
     "value_store_factory_impl.h",
     "value_store_frontend.cc",
     "value_store_frontend.h",
   ]
 
   deps = [
     "//third_party/leveldatabase",
   ]
 }