Disable folder UI when app sync is disabled

ui/app_list/views/app_list_main_view_unittest.cc

 // Copyright 2013 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 "ui/app_list/views/app_list_main_view.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "base/run_loop.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
@@ skipping 59 matching lines @@
   virtual ~AppListMainViewTest() {}
 
   // testing::Test overrides:
   virtual void SetUp() OVERRIDE {
     views::ViewsTestBase::SetUp();
     delegate_.reset(new AppListTestViewDelegate);
 
     main_view_ =
         new AppListMainView(delegate_.get(), &pagination_model_, GetContext());
     main_view_->SetPaintToLayer(true);
+    main_view_->model()->SetFoldersEnabled(true);
 
     widget_ = new views::Widget;
     views::Widget::InitParams params =
         CreateParams(views::Widget::InitParams::TYPE_POPUP);
     params.bounds.set_size(main_view_->GetPreferredSize());
     widget_->Init(params);
 
     widget_->SetContentsView(main_view_);
   }
 
@@ skipping 178 matching lines @@
   root_grid_view_test_api.LayoutToIdealBounds();
   EXPECT_EQ(first_slot_tile, RootViewModel()->view_at(0)->bounds());
 
   // Single item folder should be auto removed.
   EXPECT_EQ(NULL,
             delegate_->GetTestModel()->FindFolderItem("single_item_folder"));
 }
 
 }  // namespace test
 }  // namespace app_list