Try to get rid of all direct references to particular native themes.

ui/views/widget/native_widget_aura.cc

 // Copyright (c) 2012 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/native_widget_aura.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/memory/ptr_util.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 726 matching lines @@
       wm_transition = wm::ANIMATE_BOTH;
       break;
     case Widget::ANIMATE_NONE:
       wm_transition = wm::ANIMATE_NONE;
       break;
   }
   wm::SetWindowVisibilityAnimationTransition(window_, wm_transition);
 }
 
 ui::NativeTheme* NativeWidgetAura::GetNativeTheme() const {
-#if !defined(OS_CHROMEOS) && !defined(OS_ANDROID)
-  return DesktopWindowTreeHost::GetNativeTheme(window_);
-#else
-  return ui::NativeThemeAura::instance();
-#endif
+  return ui::NativeTheme::GetInstanceForNativeUi();
 }
 
 void NativeWidgetAura::OnRootViewLayout() {
 }
 
 bool NativeWidgetAura::IsTranslucentWindowOpacitySupported() const {
   return true;
 }
 
 void NativeWidgetAura::OnSizeConstraintsChanged() {
@@ skipping 452 matching lines @@
     gfx::NativeView native_view) {
   aura::client::CaptureClient* capture_client =
       aura::client::GetCaptureClient(native_view->GetRootWindow());
   if (!capture_client)
     return nullptr;
   return capture_client->GetGlobalCaptureWindow();
 }
 
 }  // namespace internal
 }  // namespace views