Revert of Finish eliminating PlatformWindowMus

ash/host/ash_window_tree_host_unified.cc

 // 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 "ash/host/ash_window_tree_host_unified.h"
 
 #include <utility>
 
 #include "ash/host/root_window_transformer.h"
 #include "ash/ime/input_method_event_handler.h"
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/aura/window_targeter.h"
 #include "ui/compositor/compositor.h"
 #include "ui/gfx/geometry/insets.h"
-#include "ui/gfx/native_widget_types.h"
 #include "ui/platform_window/stub/stub_window.h"
 
 namespace ash {
 
 class UnifiedEventTargeter : public aura::WindowTargeter {
  public:
   UnifiedEventTargeter(aura::Window* src_root, aura::Window* dst_root)
       : src_root_(src_root), dst_root_(dst_root) {}
 
   ui::EventTarget* FindTargetForEvent(ui::EventTarget* root,
@@ skipping 15 matching lines @@
 
   aura::Window* src_root_;
   aura::Window* dst_root_;
 
   DISALLOW_COPY_AND_ASSIGN(UnifiedEventTargeter);
 };
 
 AshWindowTreeHostUnified::AshWindowTreeHostUnified(
     const gfx::Rect& initial_bounds)
     : AshWindowTreeHostPlatform() {
-  std::unique_ptr<ui::PlatformWindow> window(
-      new ui::StubWindow(this, gfx::kNullAcceleratedWidget));
+  std::unique_ptr<ui::PlatformWindow> window(new ui::StubWindow(this));
   window->SetBounds(initial_bounds);
   SetPlatformWindow(std::move(window));
 }
 
 AshWindowTreeHostUnified::~AshWindowTreeHostUnified() {
   for (auto* ash_host : mirroring_hosts_)
     ash_host->AsWindowTreeHost()->window()->RemoveObserver(this);
 }
 
 void AshWindowTreeHostUnified::PrepareForShutdown() {
@@ skipping 39 matching lines @@
       std::find_if(mirroring_hosts_.begin(), mirroring_hosts_.end(),
                    [window](AshWindowTreeHost* ash_host) {
                      return ash_host->AsWindowTreeHost()->window() == window;
                    });
   DCHECK(iter != mirroring_hosts_.end());
   window->RemoveObserver(this);
   mirroring_hosts_.erase(iter);
 }
 
 }  // namespace ash