Don't use browser windows for platform app shell windows

chrome/browser/ui/extensions/shell_window.h

+// 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.
+
+#ifndef CHROME_BROWSER_UI_EXTENSIONS_SHELL_WINDOW_H_
+#define CHROME_BROWSER_UI_EXTENSIONS_SHELL_WINDOW_H_
+#pragma once
+
+#include "base/memory/scoped_ptr.h"
+#include "chrome/browser/extensions/extension_host.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+
+class GURL;
+class Extension;
+class ExtensionHost;
+class Profile;
+
+namespace content {
+class WebContents;
+}
+
+class ShellWindow : public content::NotificationObserver {
+ public:
+  content::WebContents* web_contents() const { return host_->host_contents(); }
+
+  static ShellWindow* Create(Profile* profile,
+                             const Extension* extension,
+                             const GURL& url);
+
+  // Closes the displayed window and invokes the destructor.
+  virtual void Close() = 0;
+
+  // content::NotificationObserver implementation.
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+ protected:
+  explicit ShellWindow(ExtensionHost* host_);
+  virtual ~ShellWindow();
+
+  // Instantiates a platform-specific ShellWindow subclass (one implementation
+  // per platform). Public users of ShellWindow should use ShellWindow::Create.
+  static ShellWindow* CreateShellWindow(ExtensionHost* host);
+
+  scoped_ptr<ExtensionHost> host_;
+
+  content::NotificationRegistrar registrar_;
+};
+
+#endif  // CHROME_BROWSER_UI_EXTENSIONS_SHELL_WINDOW_H_