linux and chromeos: Turn on -Wunused-const-variable.

ash/system/web_notification/web_notification_tray.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/web_notification/web_notification_tray.h"
 
 #include "ash/ash_switches.h"
 #include "ash/root_window_controller.h"
 #include "ash/shelf/shelf_layout_manager.h"
 #include "ash/shelf/shelf_layout_manager_observer.h"
@@ skipping 41 matching lines @@
 
 }  // namespace message_center
 
 #endif  // defined(OS_CHROMEOS)
 
 namespace ash {
 namespace {
 
 // Menu commands
 const int kToggleQuietMode = 0;
-const int kEnableQuietModeHour = 1;
 const int kEnableQuietModeDay = 2;
 
 }
 
 namespace internal {
 namespace {
 
 const SkColor kWebNotificationColorNoUnread = SkColorSetA(SK_ColorWHITE, 128);
 const SkColor kWebNotificationColorWithUnread = SK_ColorWHITE;
 
@@ skipping 535 matching lines @@
 
 message_center::MessageCenterBubble*
 WebNotificationTray::GetMessageCenterBubbleForTest() {
   if (!message_center_bubble())
     return NULL;
   return static_cast<message_center::MessageCenterBubble*>(
       message_center_bubble()->bubble());
 }
 
 }  // namespace ash