Introduces AppActivity and handler of chrome.shell API.

apps/shell/browser/shell_desktop_controller.h

Index: apps/shell/browser/shell_desktop_controller.h
diff --git a/apps/shell/browser/shell_desktop_controller.h b/apps/shell/browser/shell_desktop_controller.h
index 2c5b84636728b1ffeff9a7da9488922d44814fc4..884b18ccc6d5e0394c1751b20c714e58495085e9 100644
--- a/apps/shell/browser/shell_desktop_controller.h
+++ b/apps/shell/browser/shell_desktop_controller.h
@@ -49,6 +49,7 @@ class UserActivityDetector;
 namespace apps {
 
 class ShellAppWindow;
+class ShellAppWindowController;
 
 // Handles desktop-related tasks for app_shell.
 class ShellDesktopController : public aura::client::WindowTreeClient,
@@ -72,12 +73,14 @@ class ShellDesktopController : public aura::client::WindowTreeClient,
   // Creates the window that hosts the app.
   void CreateRootWindow();
 
+  void SetAppWindowController(ShellAppWindowController* app_window_controller);

[oshima, 2014/06/16 18:40:08]

looks like you can just pass it in ctor?

[Jun Mukai, 2014/06/16 18:48:15]

The DefaultShellAppWindowController (of app_shell) requires
ShellDesktopController's reference -- actually it needs the pointer to the root
window to create the actual window correctly (on the other hand, this is not
required at all in Athena).

After considering about this, I think it is better to create
ShellAppWindowController properly *after* ShellDesktopController is created, and
then set it. See app_shell's default_shell_browser_main_delegate.cc FYI.

[oshima, 2014/06/16 18:53:16]

I think this part needs ovehaul later on, so I'm fine if this is necessary for
now.

+
   // Creates a new app window and adds it to the desktop. The desktop maintains
   // ownership of the window.
   ShellAppWindow* CreateAppWindow(content::BrowserContext* context);
 
-  // Closes and destroys the app window.
-  void CloseAppWindow();
+  // Closes and destroys the app windows.
+  void CloseAppWindows();
 
   // Overridden from aura::client::WindowTreeClient:
   virtual aura::Window* GetDefaultParent(aura::Window* context,
@@ -130,7 +133,7 @@ class ShellDesktopController : public aura::client::WindowTreeClient,
 #endif
 
   // The desktop supports a single app window.
-  scoped_ptr<ShellAppWindow> app_window_;
+  scoped_ptr<ShellAppWindowController> app_window_controller_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellDesktopController);
 };