Move ContentAppModelBuilder to athena/extensions.

athena/main/athena_launcher.cc

Index: athena/main/athena_launcher.cc
diff --git a/athena/main/athena_launcher.cc b/athena/main/athena_launcher.cc
index 4efd3196b33be76e0cf430038932d430e68471c8..304b0f7966b4b50d81887b8f6a8639712b114a9d 100644
--- a/athena/main/athena_launcher.cc
+++ b/athena/main/athena_launcher.cc
@@ -8,8 +8,8 @@
 #include "athena/activity/public/activity_manager.h"
 #include "athena/content/public/app_registry.h"
 #include "athena/content/public/content_activity_factory_creator.h"
-#include "athena/content/public/content_app_model_builder.h"
 #include "athena/env/public/athena_env.h"
+#include "athena/extensions/public/extension_app_model_builder.h"
 #include "athena/extensions/public/extensions_delegate.h"
 #include "athena/home/public/home_card.h"
 #include "athena/input/public/input_manager.h"
@@ -131,7 +131,7 @@ void StartAthenaEnv(scoped_refptr<base::TaskRunner> file_runner) {
 
 void StartAthenaSessionWithContext(content::BrowserContext* context) {
   StartAthenaSession(athena::CreateContentActivityFactory(),
-                     new athena::ContentAppModelBuilder(context));
+                     new athena::ExtensionAppModelBuilder(context));
   athena::VirtualKeyboardManager::Create(context);
   athena::HomeCard::Get()->RegisterSearchProvider(
       new athena::UrlSearchProvider(context));