mash: Move TrayUpdate to //ash/common

ash/ash.gyp

Index: ash/ash.gyp
diff --git a/ash/ash.gyp b/ash/ash.gyp
index 60624974f68a546d90a36963bdf7e51cc5abd321..4038f4a66382d1e7bcc34fa358a0201e235a113e 100644
--- a/ash/ash.gyp
+++ b/ash/ash.gyp
@@ -113,6 +113,8 @@
       'common/system/tray/tray_utils.h',
       'common/system/tray/wm_system_tray_notifier.cc',
       'common/system/tray/wm_system_tray_notifier.h',
+      'common/system/update/tray_update.cc',
+      'common/system/update/tray_update.h',
       'common/system/update/update_observer.h',
       'common/system/volume_control_delegate.h',
       'common/wm/always_on_top_controller.cc',
@@ -600,8 +602,6 @@
       'system/tray/view_click_listener.h',
       'system/tray_accessibility.cc',
       'system/tray_accessibility.h',
-      'system/tray_update.cc',
-      'system/tray_update.h',
       'system/user/button_from_view.cc',
       'system/user/button_from_view.h',
       'system/user/login_status.cc',
@@ -897,6 +897,7 @@
       'autoclick/autoclick_unittest.cc',
       'common/material_design/material_design_controller_unittest.cc',
       'common/shelf/shelf_model_unittest.cc',
+      'common/system/update/tray_update_unittest.cc',
       'content/display/screen_orientation_controller_chromeos_unittest.cc',
       'content/keyboard_overlay/keyboard_overlay_delegate_unittest.cc',
       'content/keyboard_overlay/keyboard_overlay_view_unittest.cc',
@@ -970,7 +971,6 @@
       'system/tray/media_security/multi_profile_media_tray_item_unittest.cc',
       'system/tray/system_tray_unittest.cc',
       'system/tray/tray_details_view_unittest.cc',
-      'system/tray_update_unittest.cc',
       'system/user/tray_user_unittest.cc',
       'system/web_notification/ash_popup_alignment_delegate_unittest.cc',
       'system/web_notification/web_notification_tray_unittest.cc',