Use Ash's ShelfWindowWatcher for app panel windows.

ash/shell/panel_window.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 "ash/shell/panel_window.h"
 
 #include "ash/common/wm/panels/panel_frame_view.h"
 #include "ash/screen_util.h"
 #include "ash/shell.h"
+#include "ash/wm/window_properties.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/aura/window.h"
-#include "ui/aura/window_event_dispatcher.h"
 #include "ui/gfx/canvas.h"
 #include "ui/views/widget/widget.h"
 
 namespace {
 const int kMinWidth = 100;
 const int kMinHeight = 100;
 const int kDefaultWidth = 200;
 const int kDefaultHeight = 300;
 }
 
@@ skipping 19 matching lines @@
 
   if (params().bounds.width() == 0)
     params().bounds.set_width(kDefaultWidth);
   if (params().bounds.height() == 0)
     params().bounds.set_height(kDefaultHeight);
   params().bounds = ScreenUtil::ConvertRectToScreen(
       Shell::GetTargetRootWindow(), params().bounds);
 
   widget->Init(params());
   widget->GetNativeView()->SetName(name_);
+  widget->GetNativeWindow()->SetProperty<int>(kShelfItemTypeKey,
+                                              TYPE_APP_PANEL);
   widget->Show();
 
   return widget;
 }
 
 gfx::Size PanelWindow::GetPreferredSize() const {
   return gfx::Size(kMinWidth, kMinHeight);
 }
 
 void PanelWindow::OnPaint(gfx::Canvas* canvas) {
@@ skipping 15 matching lines @@
 bool PanelWindow::CanMinimize() const {
   return false;
 }
 
 views::NonClientFrameView* PanelWindow::CreateNonClientFrameView(
     views::Widget* widget) {
   return new PanelFrameView(widget, PanelFrameView::FRAME_NONE);
 }
 
 }  // namespace ash