aura: Require explicit ownership of the Env instance.

ash/test/ash_interactive_ui_test_base.cc

 // Copyright 2015 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.
 
 #include "ash/test/ash_interactive_ui_test_base.h"
 
 #include "base/path_service.h"
 #include "ui/aura/env.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/ui_base_paths.h"
@@ skipping 11 matching lines @@
 
   ui::RegisterPathProvider();
   ui::ResourceBundle::InitSharedInstanceWithLocale(
       "en-US", NULL, ui::ResourceBundle::LOAD_COMMON_RESOURCES);
   base::FilePath resources_pack_path;
   PathService::Get(base::DIR_MODULE, &resources_pack_path);
   resources_pack_path =
       resources_pack_path.Append(FILE_PATH_LITERAL("resources.pak"));
   ResourceBundle::GetSharedInstance().AddDataPackFromPath(
       resources_pack_path, ui::SCALE_FACTOR_NONE);
-  aura::Env::CreateInstance(true);
+  env_ = aura::Env::CreateInstance();
 
   test::AshTestBase::SetUp();
 }
 
 void AshInteractiveUITestBase::TearDown() {
   test::AshTestBase::TearDown();
-  aura::Env::DeleteInstance();
+  env_.reset();
 }
 
 }  // namespace test
 }  // namespace ash