Revert of Introduce AndroidFocusRules and NativeWidgetAndroid

ui/views/widget/android/android_focus_rules.cc

Index: ui/views/widget/android/android_focus_rules.cc
diff --git a/ui/views/widget/android/android_focus_rules.cc b/ui/views/widget/android/android_focus_rules.cc
deleted file mode 100644
index c01ace9ca58af9f1e1cc6116ca25e1b31a69cf9d..0000000000000000000000000000000000000000
--- a/ui/views/widget/android/android_focus_rules.cc
+++ /dev/null
@@ -1,19 +0,0 @@
-// 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.
-
-#include "ui/views/widget/android/android_focus_rules.h"
-
-#include "ui/aura/window.h"
-
-namespace views {
-
-AndroidFocusRules::AndroidFocusRules() {}
-
-AndroidFocusRules::~AndroidFocusRules() {}
-
-bool AndroidFocusRules::SupportsChildActivation(aura::Window* window) const {
-  return window->IsRootWindow();
-}
-
-}  // namespace views