Add ScopedMacRTL class for Cocoa browser RTL testing

chrome/browser/ui/cocoa/test/scoped_force_rtl_mac.h

+// 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.
+
+#ifndef CHROME_BROWSER_UI_COCOA_TEST_SCOPED_FORCE_RTL_MAC_H__
+#define CHROME_BROWSER_UI_COCOA_TEST_SCOPED_FORCE_RTL_MAC_H__
+
+#include <string>
+
+#include "base/test/scoped_feature_list.h"
+
+namespace cocoa_l10n_util {
+
+// Enables all flags required for
+// |cocoa_l10n_util::ShouldDoExperimentalRTLLayout| to return true.
+class ScopedForceRTLMac final {
+ public:
+  ScopedForceRTLMac();
+  ~ScopedForceRTLMac();
+
+ private:
+  BOOL original_apple_text_direction_;
+  BOOL original_rtl_writing_direction_;
+  std::string original_locale_;
+  base::test::ScopedFeatureList scoped_feature_list_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedForceRTLMac);
+};
+
+}  // namespace cocoa_l10n_util
+
+#endif  // CHROME_BROWSER_UI_COCOA_TEST_SCOPED_FORCE_RTL_MAC_H__