Re-land: Resurrect Aura Linux accessibility.

ui/accessibility/platform/atk_util_auralinux.h

+// 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.
+
+#ifndef UI_ACCESSIBILITY_AX_UTIL_AURALINUX_H_
+#define UI_ACCESSIBILITY_AX_UTIL_AURALINUX_H_
+
+#include "base/memory/singleton.h"
+#include "ui/accessibility/ax_export.h"
+
+namespace ui {
+
+// This singleton class initializes ATK (accessibility toolkit) and
+// registers an implementation of the AtkUtil class, a global class that
+// every accessible application needs to register once.
+class AtkUtilAuraLinux {
+ public:
+  // Get the single instance of this class.
+  static AtkUtilAuraLinux* GetInstance();
+
+  AtkUtilAuraLinux();
+  virtual ~AtkUtilAuraLinux();
+
+ private:
+  friend struct DefaultSingletonTraits<AtkUtilAuraLinux>;
+};
+
+}  // namespace ui
+
+#endif  // UI_ACCESSIBILITY_AX_UTIL_AURALINUX_H_