Remove (Native)Widget::StackBelow().

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 447 matching lines @@
   if (window_ && window_->parent() &&
       window_->parent() == native_view->parent())
     window_->parent()->StackChildAbove(window_, native_view);
 }
 
 void NativeWidgetAura::StackAtTop() {
   if (window_)
     window_->parent()->StackChildAtTop(window_);
 }
 
-void NativeWidgetAura::StackBelow(gfx::NativeView native_view) {
-  if (window_ && window_->parent() &&
-      window_->parent() == native_view->parent())
-    window_->parent()->StackChildBelow(window_, native_view);
-}
-
 void NativeWidgetAura::SetShape(std::unique_ptr<SkRegion> region) {
   if (window_)
     window_->layer()->SetAlphaShape(std::move(region));
 }
 
 void NativeWidgetAura::Close() {
   // |window_| may already be deleted by parent window. This can happen
   // when this widget is child widget or has transient parent
   // and ownership is WIDGET_OWNS_NATIVE_WIDGET.
   DCHECK(window_ ||
@@ skipping 737 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