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

chrome/browser/lifetime/application_lifetime.h

Index: chrome/browser/lifetime/application_lifetime.h
===================================================================
--- chrome/browser/lifetime/application_lifetime.h	(revision 169752)
+++ chrome/browser/lifetime/application_lifetime.h	(working copy)
@@ -5,6 +5,8 @@
 #ifndef CHROME_BROWSER_LIFETIME_APPLICATION_LIFETIME_H_
 #define CHROME_BROWSER_LIFETIME_APPLICATION_LIFETIME_H_
 
+#include "chrome/browser/ui/host_desktop.h"
+
 namespace browser {
 
 // Starts a user initiated exit process. Called from Browser::Exit.
@@ -51,6 +53,9 @@
 // message.
 void CloseAllBrowsers();
 
+// Closes all browsers of the type (Desktop/Ash) passed in.
+void CloseAllBrowsersOfType(chrome::HostDesktopType type);
+
 // Begins shutdown of the application when the desktop session is ending.
 void SessionEnding();