Revert of Introduce AndroidFocusRules and NativeWidgetAndroid

ui/views/widget/android/android_focus_rules.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_VIEWS_WIDGET_ANDROID_ANDROID_FOCUS_RULES_H_
-#define UI_VIEWS_WIDGET_ANDROID_ANDROID_FOCUS_RULES_H_
-
-#include "base/macros.h"
-#include "ui/wm/core/base_focus_rules.h"
-
-namespace views {
-
-// A set of focus rules for Android using aura.
-class AndroidFocusRules : public wm::BaseFocusRules {
- public:
-  AndroidFocusRules();
-  ~AndroidFocusRules() override;
-
- private:
-  // wm::BaseFocusRules:
-  bool SupportsChildActivation(aura::Window* window) const override;
-
-  DISALLOW_COPY_AND_ASSIGN(AndroidFocusRules);
-};
-
-}  // namespace views
-
-#endif  // UI_VIEWS_WIDGET_ANDROID_ANDROID_FOCUS_RULES_H_