Move ownership of AppSorting from ExtensionPrefs to ExtensionSystem

extensions/browser/app_window/app_window_geometry_cache_unittest.cc

Index: extensions/browser/app_window/app_window_geometry_cache_unittest.cc
diff --git a/extensions/browser/app_window/app_window_geometry_cache_unittest.cc b/extensions/browser/app_window/app_window_geometry_cache_unittest.cc
index e1f4068440298217262576b2c982b80a4972d15f..1600693ae181cfb45aa3f51360583df1cb3da0d7 100644
--- a/extensions/browser/app_window/app_window_geometry_cache_unittest.cc
+++ b/extensions/browser/app_window/app_window_geometry_cache_unittest.cc
@@ -95,9 +95,10 @@ void AppWindowGeometryCacheTest::SetUp() {
       pref_service_.get(),
       browser_context()->GetPath().AppendASCII("Extensions"),
       extension_pref_value_map_.get(),
-      scoped_ptr<AppSorting>(new NullAppSorting),
       false /* extensions_disabled */,
       std::vector<ExtensionPrefsObserver*>()));
+  scoped_ptr<AppSorting> app_sorting(new NullAppSorting);
+  extension_prefs_->set_app_sorting(app_sorting.get());
 
   cache_.reset(
       new AppWindowGeometryCache(browser_context(), extension_prefs_.get()));