Add palette tray to ash.

ash/common/system/status_area_widget.h

Index: ash/common/system/status_area_widget.h
diff --git a/ash/common/system/status_area_widget.h b/ash/common/system/status_area_widget.h
index a8c8c1f829049ebd8bec62ece756dd1422c6ceb4..550555f7370f7d582aeb9ba477fa5ea9079a5dcc 100644
--- a/ash/common/system/status_area_widget.h
+++ b/ash/common/system/status_area_widget.h
@@ -22,6 +22,7 @@ class WmWindow;
 #if defined(OS_CHROMEOS)
 class ImeMenuTray;
 class LogoutButtonTray;
+class PaletteTray;
 class VirtualKeyboardTray;
 #endif
 
@@ -79,6 +80,7 @@ class ASH_EXPORT StatusAreaWidget : public views::Widget {
   void AddWebNotificationTray();
 #if defined(OS_CHROMEOS)
   void AddLogoutButtonTray();
+  void AddPaletteTray();
   void AddVirtualKeyboardTray();
   void AddImeMenuTray();
 #endif
@@ -91,6 +93,7 @@ class ASH_EXPORT StatusAreaWidget : public views::Widget {
   WebNotificationTray* web_notification_tray_;
 #if defined(OS_CHROMEOS)
   LogoutButtonTray* logout_button_tray_;
+  PaletteTray* palette_tray_;
   VirtualKeyboardTray* virtual_keyboard_tray_;
   ImeMenuTray* ime_menu_tray_;
 #endif