Don't use browser windows for platform app shell windows

chrome/browser/extensions/extension_process_manager.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 "base/bind.h"
 #include "base/command_line.h"
 #include "chrome/browser/extensions/extension_process_manager.h"
 
 #include "chrome/browser/ui/browser_window.h"
 #include "content/browser/browsing_instance.h"
@@ skipping 98 matching lines @@
                  content::Source<Profile>(profile));
   registrar_.Add(this, content::NOTIFICATION_APP_TERMINATING,
                  content::NotificationService::AllSources());
 }
 
 ExtensionProcessManager::~ExtensionProcessManager() {
   CloseBackgroundHosts();
   DCHECK(background_hosts_.empty());
 }
 
+ExtensionHost* ExtensionProcessManager::CreateShellHost(
+    const Extension* extension,
+    const GURL& url) {
+  DCHECK(extension);
+  ExtensionHost* host = new ExtensionHost(extension,
+                                          GetSiteInstanceForURL(url),
+                                          url,
+                                          chrome::VIEW_TYPE_APP_SHELL);
+  host->CreateViewWithoutBrowser();
+  OnExtensionHostCreated(host, false /* not a background host */);
+  return host;
+}
+
 ExtensionHost* ExtensionProcessManager::CreateViewHost(
     const Extension* extension,
     const GURL& url,
     Browser* browser,
     content::ViewType view_type) {
   DCHECK(extension);
   // A NULL browser may only be given for pop-up views.
   DCHECK(browser ||
          (!browser && view_type == chrome::VIEW_TYPE_EXTENSION_POPUP));
   ExtensionHost* host =
@@ skipping 356 matching lines @@
         if (service && service->is_ready())
           CreateBackgroundHostsForProfileStartup(this, service->extensions());
       }
       break;
     }
     default:
       ExtensionProcessManager::Observe(type, source, details);
       break;
   }
 }