Separate athena's startup process from AppShell's

extensions/shell/browser/desktop_controller.h

+// Copyright 2014 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 EXTENSIONS_SHELL_BROWSER_DESKTOP_CONTROLLER_H_
+#define EXTENSIONS_SHELL_BROWSER_DESKTOP_CONTROLLER_H_
+
+namespace aura {
+class WindowTreeHost;
+}
+
+namespace content {
+class BrowserContext;
+}
+
+namespace extensions {
+class Extension;
+class ShellAppWindow;
+
+class DesktopController {

[James Cook, 2014/08/25 16:56:14]

nit: Please comment on the purpose of this class.

[oshima, 2014/08/25 17:29:32]

Done.

+ public:
+  DesktopController();
+  virtual ~DesktopController();
+
+  // Returns the single instance of the desktop. (Stateless functions like
+  // ShellAppWindowCreateFunction need to be able to access the desktop, so
+  // we need a singleton somewhere).
+  static DesktopController* instance();
+
+  virtual aura::WindowTreeHost* GetHost() = 0;

[James Cook, 2014/08/25 16:56:14]

nit: function comment

(I know it seems stupid, but these sorts of comments make a big difference for
me when I'm exploring new regions of the code.)

[oshima, 2014/08/25 17:29:32]

I'm fine. Different people have different preference :)

+
+  // Creates a new app window and adds it to the desktop. The desktop maintains
+  // ownership of the window. The window must be closed before |extension| is
+  // destroyed.
+  virtual ShellAppWindow* CreateAppWindow(content::BrowserContext* context,
+                                          const Extension* extension) = 0;
+
+  // Closes and destroys the app windows.
+  virtual void CloseAppWindows() = 0;
+};
+
+}  // namespace extensinos
+
+#endif  //  EXTENSIONS_SHELL_BROWSER_DESKTOP_CONTROLLER_H_

[James Cook, 2014/08/25 16:56:14]

nit: one space after //

[oshima, 2014/08/25 17:29:32]

Done.