mash: Move SystemTrayDelegate and dependencies to //ash/common

ash/ash.gyp

Index: ash/ash.gyp
diff --git a/ash/ash.gyp b/ash/ash.gyp
index 4ddafac5b7500256d0ff820919c491260ef64f2c..b25a25c424d16b0f3f69f51567387bf56d063aa1 100644
--- a/ash/ash.gyp
+++ b/ash/ash.gyp
@@ -93,6 +93,14 @@
       'common/shelf/wm_shelf_util.h',
       'common/shell_window_ids.cc',
       'common/shell_window_ids.h',
+      'common/system/networking_config_delegate.cc',
+      'common/system/networking_config_delegate.h',
+      'common/system/tray/default_system_tray_delegate.cc',
+      'common/system/tray/default_system_tray_delegate.h',
+      'common/system/tray/system_tray_delegate.cc',
+      'common/system/tray/system_tray_delegate.h',
+      'common/system/update/update_observer.h',
+      'common/system/volume_control_delegate.h',
       'common/wm/always_on_top_controller.cc',
       'common/wm/always_on_top_controller.h',
       'common/wm/background_animator.cc',
@@ -327,8 +335,6 @@
       'metrics/user_metrics_recorder.h',
       'multi_profile_uma.cc',
       'multi_profile_uma.h',
-      'networking_config_delegate.cc',
-      'networking_config_delegate.h',
       'pointer_watcher_delegate.h',
       'pointer_watcher_delegate_aura.cc',
       'pointer_watcher_delegate_aura.h',
@@ -534,8 +540,6 @@
       'system/toast/toast_overlay.h',
       'system/tray/actionable_view.cc',
       'system/tray/actionable_view.h',
-      'system/tray/default_system_tray_delegate.cc',
-      'system/tray/default_system_tray_delegate.h',
       'system/tray/fixed_sized_image_view.cc',
       'system/tray/fixed_sized_image_view.h',
       'system/tray/fixed_sized_scroll_view.cc',
@@ -551,8 +555,6 @@
       'system/tray/system_tray.h',
       'system/tray/system_tray_bubble.cc',
       'system/tray/system_tray_bubble.h',
-      'system/tray/system_tray_delegate.cc',
-      'system/tray/system_tray_delegate.h',
       'system/tray/system_tray_item.cc',
       'system/tray/system_tray_item.h',
       'system/tray/system_tray_notifier.cc',
@@ -606,7 +608,6 @@
       'system/user/tray_user.h',
       'system/user/tray_user_separator.cc',
       'system/user/tray_user_separator.h',
-      'system/user/update_observer.h',
       'system/user/user_card_view.cc',
       'system/user/user_card_view.h',
       'system/user/user_observer.h',
@@ -636,7 +637,6 @@
       'utility/screenshot_controller.h',
       'virtual_keyboard_controller.cc',
       'virtual_keyboard_controller.h',
-      'volume_control_delegate.h',
       'wm/ash_focus_rules.cc',
       'wm/ash_focus_rules.h',
       'wm/ash_native_cursor_manager.cc',