Introduces AppActivity and handler of chrome.shell API.

athena/main/athena_main.cc

Index: athena/main/athena_main.cc
diff --git a/athena/main/athena_main.cc b/athena/main/athena_main.cc
index d76dc66aad89ba3582f628951dce46a338bd8937..f12006cb476eb9013dbd5fdfbc6ec6924da9da3e 100644
--- a/athena/main/athena_main.cc
+++ b/athena/main/athena_main.cc
@@ -9,6 +9,7 @@
 #include "athena/content/public/content_activity_factory.h"
 #include "athena/content/public/content_app_model_builder.h"
 #include "athena/home/public/home_card.h"
+#include "athena/main/athena_app_window_controller.h"
 #include "athena/main/athena_launcher.h"
 #include "athena/main/placeholder.h"
 #include "athena/main/url_search_provider.h"
@@ -53,7 +54,9 @@ class AthenaBrowserMainDelegate : public apps::ShellBrowserMainDelegate {
   virtual apps::ShellDesktopController* CreateDesktopController() OVERRIDE {
     // TODO(mukai): create Athena's own ShellDesktopController subclass so that
     // it can initialize its own window manager logic.
-    return new apps::ShellDesktopController();
+    apps::ShellDesktopController* desktop = new apps::ShellDesktopController();
+    desktop->SetAppWindowController(new athena::AthenaAppWindowController());
+    return desktop;
   }
 
  private: