In Chrome ASH on Windows 8 make sure that the browser object is closed before destroying it.

chrome/browser/metro_viewer/metro_viewer_process_host_win.cc

 // Copyright 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 "chrome/browser/metro_viewer/metro_viewer_process_host_win.h"
 
 #include "base/logging.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/lifetime/application_lifetime.h"
 #include "chrome/browser/ui/ash/ash_init.h"
@@ skipping 36 matching lines @@
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void  MetroViewerProcessHost::OnChannelError() {
   // TODO(cpu): At some point we only close the browser. Right now this
   // is very convenient for developing.
   DLOG(INFO) << "viewer channel error : Quitting browser";
   g_browser_process->ReleaseModule();
+  browser::CloseAllBrowsersOfType(chrome::HOST_DESKTOP_TYPE_ASH);
   chrome::CloseAsh();
 }
 
 void MetroViewerProcessHost::OnSetTargetSurface(
     gfx::NativeViewId target_surface) {
   DLOG(INFO) << __FUNCTION__ << ", target_surface = " << target_surface;
   HWND hwnd = reinterpret_cast<HWND>(target_surface);
 
   chrome::OpenAsh();
 
@@ skipping 35 matching lines @@
                                     uint32 scan_code,
                                     uint32 flags) {
   aura::RemoteRootWindowHostWin::Instance()->OnChar(
       key_code, repeat_count, scan_code, flags);
 }
 
 void MetroViewerProcessHost::OnVisibilityChanged(bool visible) {
   aura::RemoteRootWindowHostWin::Instance()->OnVisibilityChanged(
       visible);
 }