Turn of ash notification tray by default for M21.

ash/system/power/tray_power.cc

 // 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.
 
 #include "ash/system/power/tray_power.h"
 
 #include "ash/ash_switches.h"
 #include "ash/shell.h"
 #include "ash/system/date/date_view.h"
 #include "ash/system/power/power_status_view.h"
@@ skipping 192 matching lines @@
 
 void TrayPower::UpdateAfterLoginStatusChange(user::LoginStatus status) {
 }
 
 void TrayPower::OnPowerStatusChanged(const PowerSupplyStatus& status) {
   if (power_tray_)
     power_tray_->UpdatePowerStatus(status);
   if (notification_view_)
     notification_view_->UpdatePowerStatus(status);
 
-  if (!CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kAshNotifyDisabled)) {
+  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kAshNotify)) {
     if (UpdateNotificationState(status))
       ShowNotificationView();
     else if (notification_state_ == NOTIFICATION_NONE)
       HideNotificationView();
   }
 }
 
 bool TrayPower::UpdateNotificationState(const PowerSupplyStatus& status) {
   if (!status.battery_is_present ||
       status.is_calculating_battery_time ||
@@ skipping 26 matching lines @@
       return false;
     case NOTIFICATION_CRITICAL:
       return false;
   }
   NOTREACHED();
   return false;
 }
 
 }  // namespace internal
 }  // namespace ash