Reverting this as it breaks (at least) the Windows Aura build.

chrome/browser/chromeos/status/status_area_view_chromeos.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_STATUS_STATUS_AREA_VIEW_CHROMEOS_H_
 #define CHROME_BROWSER_CHROMEOS_STATUS_STATUS_AREA_VIEW_CHROMEOS_H_
 #pragma once
 
 #include "chrome/browser/chromeos/status/status_area_view.h"
 
 #include "chrome/browser/chromeos/cros/power_library.h"
 #include "chrome/browser/chromeos/system/timezone_settings.h"
 #include "chrome/browser/chromeos/view_ids.h"
 
-class ClockMenuButton;
-
 namespace chromeos {
 
 class StatusAreaViewChromeos : public StatusAreaView,
                                public PowerLibrary::Observer,
                                public system::TimezoneSettings::Observer {
  public:
   // The type of screen the host window is on.
   enum ScreenMode {
     LOGIN_MODE_VIEWS,    // The host is for the views-based OOBE/login screens.
     LOGIN_MODE_WEBUI,    // The host is for the WebUI OOBE/login screens.
     BROWSER_MODE,        // The host is for browser.
     SCREEN_LOCKER_MODE,  // The host is for screen locker.
   };
 
   explicit StatusAreaViewChromeos();
   virtual ~StatusAreaViewChromeos();
 
   void Init(StatusAreaButton::Delegate* delegate, ScreenMode screen_mode);
 
   // PowerLibrary::Observer:
   virtual void SystemResumed() OVERRIDE;
 
   // TimezoneSettings::Observer:
   virtual void TimezoneChanged(const icu::TimeZone& timezone) OVERRIDE;
 
   // Sets default use 24hour clock mode.
   void SetDefaultUse24HourClock(bool use_24hour_clock);
 
   // Convenience function to add buttons to a status area for ChromeOS.
-  // |clock_button| (if non-NULL) is set to the ClockMenuButton that is created
-  // by this method.
   static void AddChromeosButtons(StatusAreaView* status_area,
                                  StatusAreaButton::Delegate* delegate,
-                                 ScreenMode screen_mode,
-                                 ClockMenuButton** clock_button);
+                                 ScreenMode screen_mode);
 
  private:
   void UpdateClockText();
 
   DISALLOW_COPY_AND_ASSIGN(StatusAreaViewChromeos);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_STATUS_STATUS_AREA_VIEW_CHROMEOS_H_