Introduce AndroidFocusRules and NativeWidgetAndroid

ui/wm/android/android_focus_rules.h

+// Copyright (c) 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_WM_ANDROID_ANDROID_FOCUS_RULES_H_
+#define UI_WM_ANDROID_ANDROID_FOCUS_RULES_H_
+
+#include "base/macros.h"
+#include "ui/wm/core/base_focus_rules.h"
+
+namespace wm {
+
+// A set of focus rules for Android using aura.
+class AndroidFocusRules : public BaseFocusRules {
+ public:
+  AndroidFocusRules();
+  ~AndroidFocusRules() override;
+
+ private:
+  // ::wm::BaseFocusRules:
+  bool SupportsChildActivation(aura::Window* window) const override;
+
+  DISALLOW_COPY_AND_ASSIGN(AndroidFocusRules);
+};
+
+}  // namespace wm
+
+#endif  // UI_WM_ANDROID_ANDROID_FOCUS_RULES_H_