Don't use browser windows for platform app shell windows

chrome/browser/ui/gtk/browser_window_gtk.cc

 // Copyright (c) 2011 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 "chrome/browser/ui/gtk/browser_window_gtk.h"
 
 #include <gdk/gdkkeysyms.h>
 
 #include <dlfcn.h>
 #include <string>
@@ skipping 1899 matching lines @@
         accel_group_,
         iter->second.GetGdkKeyCode(),
         static_cast<GdkModifierType>(iter->second.modifiers()),
         GtkAccelFlags(0),
         g_cclosure_new(G_CALLBACK(OnGtkAccelerator),
                        GINT_TO_POINTER(iter->first), NULL));
   }
 }
 
 void BrowserWindowGtk::UpdateCustomFrame() {
-  gtk_window_set_decorated(
-      window_, !UseCustomFrame() && browser_->type() != Browser::TYPE_SHELL);
+  gtk_window_set_decorated(window_, !UseCustomFrame());
   titlebar_->UpdateCustomFrame(UseCustomFrame() && !IsFullscreen());
   UpdateWindowShape(bounds_.width(), bounds_.height());
 }
 
 gfx::Size BrowserWindowGtk::GetNonClientFrameSize() const {
   GtkAllocation window_container_allocation;
   gtk_widget_get_allocation(window_container_, &window_container_allocation);
   GtkAllocation render_area_floating_container_allocation;
   gtk_widget_get_allocation(render_area_floating_container_,
                             &render_area_floating_container_allocation);
@@ skipping 518 matching lines @@
           wm_type == ui::WM_OPENBOX ||
           wm_type == ui::WM_XFWM4);
 }
 
 // static
 BrowserWindow* BrowserWindow::CreateBrowserWindow(Browser* browser) {
   BrowserWindowGtk* browser_window_gtk = new BrowserWindowGtk(browser);
   browser_window_gtk->Init();
   return browser_window_gtk;
 }