Clean up unused grit header includes in ash/.

ash/system/tray/tray_details_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 "ash/system/tray/tray_details_view.h"
 
 #include "ash/ash_view_ids.h"
-#include "ash/resources/grit/ash_resources.h"
 #include "ash/strings/grit/ash_strings.h"
 #include "ash/system/tray/system_tray.h"
 #include "ash/system/tray/system_tray_item.h"
 #include "ash/system/tray/tray_constants.h"
 #include "ash/system/tray/tray_popup_header_button.h"
 #include "ash/system/tray/view_click_listener.h"
 #include "ash/test/ash_test_base.h"
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
 #include "base/test/scoped_mock_time_message_loop_task_runner.h"
@@ skipping 207 matching lines @@
 
   // Sticky header layer should be above the last child's layer.
   EXPECT_EQ(3u, layers.size());
   EXPECT_EQ(view3->layer(), layers[0]);
   EXPECT_EQ(view4->layer(), layers[1]);
   EXPECT_EQ(view2->layer(), layers[2]);
 }
 
 }  // namespace test
 }  // namespace ash