Separate athena's startup process from AppShell's

extensions/shell/browser/desktop_controller.h

Index: extensions/shell/browser/desktop_controller.h
diff --git a/extensions/shell/browser/desktop_controller.h b/extensions/shell/browser/desktop_controller.h
new file mode 100644
index 0000000000000000000000000000000000000000..6a101ba440e40c58dfd41373892b3e2c0c2743cd
--- /dev/null
+++ b/extensions/shell/browser/desktop_controller.h
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+// 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 ShellAppWindow;
+
+class DesktopController {
+ 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;
+
+  // Creates the window that hosts the app.
+  virtual void CreateRootWindow() = 0;
+
+  // Creates a new app window and adds it to the desktop. The desktop maintains
+  // ownership of the window.
+  virtual ShellAppWindow* CreateAppWindow(content::BrowserContext* context) = 0;
+
+  // Closes and destroys the app windows.
+  virtual void CloseAppWindows() = 0;
+};
+
+}  // namespace extensinos
+
+#endif  //  EXTENSIONS_SHELL_BROWSER_DESKTOP_CONTROLLER_H_