Added arrow key navigation to 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',
   },
   'targets': [
@@ skipping 570 matching lines @@
         'wm/maximize_mode/workspace_backdrop_delegate.cc',
         'wm/maximize_mode/workspace_backdrop_delegate.h',
         'wm/mru_window_tracker.cc',
         'wm/mru_window_tracker.h',
         'wm/overlay_event_filter.cc',
         'wm/overlay_event_filter.h',
         'wm/overview/scoped_transform_overview_window.cc',
         'wm/overview/scoped_transform_overview_window.h',
         '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',
@@ skipping 613 matching lines @@
       'conditions': [
         ['chromeos==1', {
           'dependencies': [
             '../ui/display/display.gyp:display',
           ],
         }],
       ],
     },
   ],
 }