Revert "Fix a ton of compiler warnings."

base/system_monitor.h

-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Copyright (c) 2008 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 BASE_SYSTEM_MONITOR_H_
 #define BASE_SYSTEM_MONITOR_H_
 
 #include "build/build_config.h"
 
 // Windows HiRes timers drain the battery faster so we need to know the battery
 // status.  This isn't true for other platforms.
@@ skipping 53 matching lines @@
    public:
     // Notification of a change in power status of the computer, such
     // as from switching between battery and A/C power.
     virtual void OnPowerStateChange(SystemMonitor*) = 0;
 
     // Notification that the system is suspending.
     virtual void OnSuspend(SystemMonitor*) = 0;
 
     // Notification that the system is resuming.
     virtual void OnResume(SystemMonitor*) = 0;
-
-   protected:
-    ~PowerObserver() {}
   };
 
   // Add a new observer.
   // Can be called from any thread.
   // Must not be called from within a notification callback.
   void AddObserver(PowerObserver* obs);
 
   // Remove an existing observer.
   // Can be called from any thread.
   // Must not be called from within a notification callback.
@@ skipping 35 matching lines @@
 #if defined(ENABLE_BATTERY_MONITORING)
   base::OneShotTimer<SystemMonitor> delayed_battery_check_;
 #endif
 
   DISALLOW_COPY_AND_ASSIGN(SystemMonitor);
 };
 
 }
 
 #endif  // BASE_SYSTEM_MONITOR_H_