Introduces --app flag to athena to load an app.

apps/shell/browser/shell_extension_system.h

Index: apps/shell/browser/shell_extension_system.h
diff --git a/apps/shell/browser/shell_extension_system.h b/apps/shell/browser/shell_extension_system.h
index a287d2d1fb74084c5e09c98a43e61c0442ee81ca..3ddd3ff1e17256a5da64375f6efd4281cd6db74a 100644
--- a/apps/shell/browser/shell_extension_system.h
+++ b/apps/shell/browser/shell_extension_system.h
@@ -36,10 +36,15 @@ class ShellExtensionSystem : public ExtensionSystem {
   explicit ShellExtensionSystem(content::BrowserContext* browser_context);
   virtual ~ShellExtensionSystem();
 
-  // Loads an unpacked application from a directory and attempts to launch it.
-  // Returns true on success.
+  // Runs LoadApp() and LaunchApp().
   bool LoadAndLaunchApp(const base::FilePath& app_dir);
 
+  // Loads an unpacked application from a directory. Returns true on success.
+  bool LoadApp(const base::FilePath& app_dir);
+
+  // Launch the currently loaded app.
+  void LaunchApp();
+
   // KeyedService implementation:
   virtual void Shutdown() OVERRIDE;
 
@@ -75,6 +80,8 @@ class ShellExtensionSystem : public ExtensionSystem {
   // Extension ID for the app.
   std::string app_id_;
 
+  scoped_refptr<Extension> extension_;
+
   // Data to be accessed on the IO thread. Must outlive process_manager_.
   scoped_refptr<InfoMap> info_map_;