Upstream Chrome on iOS source code [10/11].

ios/chrome/test/app/stack_view_test_util.mm

+// 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 "ios/chrome/test/app/stack_view_test_util.h"
+
+#import "base/mac/foundation_util.h"
+#import "ios/chrome/app/main_controller.h"
+#import "ios/chrome/app/main_controller_private.h"
+#import "ios/chrome/browser/ui/stack_view/stack_view_controller.h"
+#import "ios/chrome/test/app/chrome_test_util.h"
+#import "ios/chrome/test/app/tab_test_util.h"
+
+namespace chrome_test_util {
+
+bool IsTabSwitcherActive() {
+  return [chrome_test_util::GetMainController() isTabSwitcherActive];
+}
+
+StackViewController* GetStackViewController() {
+  if (!IsTabSwitcherActive())
+    return nil;
+  MainController* mainController = chrome_test_util::GetMainController();
+  DCHECK(mainController);
+  return base::mac::ObjCCastStrict<StackViewController>(
+      [mainController tabSwitcherController]);
+}
+
+}  // namespace chrome_test_util