Move app_shell specific impl from athena_lib to athena_shell_lib

athena/content/content_activity_factory.cc

 // 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.
 
-#include "athena/content/public/content_activity_factory.h"
+#include "athena/content/content_activity_factory.h"
 
-#include "athena/content/app_activity.h"
 #include "athena/content/web_activity.h"
 #include "base/logging.h"
 
 namespace athena {
 
 ContentActivityFactory::ContentActivityFactory() {
 }
 
 ContentActivityFactory::~ContentActivityFactory() {}
 
 Activity* ContentActivityFactory::CreateWebActivity(
     content::BrowserContext* browser_context,
     const GURL& url) {
   return new WebActivity(browser_context, url);
 }
 
-Activity* ContentActivityFactory::CreateAppActivity(
-    extensions::ShellAppWindow* app_window) {
-  return new AppActivity(app_window);
+ActivityFactory* CreateContentActivityFactory() {
+  return new ContentActivityFactory();
 }
 
 }  // namespace athena