Remove TransparentActivateWindowButton from Overview Mode

ash/ash.gyp

 # Copyright (c) 2012 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.
 
 {
   'variables': {
     'chromium_code': 1,
     'grit_out_dir': '<(SHARED_INTERMEDIATE_DIR)/chrome',
     # These files lists are shared with the GN build.
     'ash_sources': [
@@ skipping 536 matching lines @@
       'wm/overview/scoped_window_copy.cc',
       'wm/overview/scoped_window_copy.h',
       'wm/overview/window_grid.cc',
       'wm/overview/window_grid.h',
       'wm/overview/window_selector.cc',
       'wm/overview/window_selector.h',
       'wm/window_cycle_controller.cc',
       'wm/window_cycle_controller.h',
       'wm/window_cycle_list.cc',
       'wm/window_cycle_list.h',
-      'wm/overview/transparent_activate_window_button.cc',
-      'wm/overview/transparent_activate_window_button.h',
       'wm/overview/window_selector_controller.cc',
       'wm/overview/window_selector_controller.h',
       'wm/overview/window_selector_delegate.h',
       'wm/overview/window_selector_item.cc',
       'wm/overview/window_selector_item.h',
       'wm/panels/attached_panel_window_targeter.cc',
       'wm/panels/attached_panel_window_targeter.h',
       'wm/panels/panel_frame_view.cc',
       'wm/panels/panel_frame_view.h',
       'wm/panels/panel_layout_manager.cc',
@@ skipping 713 matching lines @@
             '../build/isolate.gypi',
           ],
           'sources': [
             'ash_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }