Revert "Fix a ton of compiler warnings."

chrome/browser/renderer_host/render_widget_host_painting_observer.h

 // Copyright (c) 2009 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_RENDERER_HOST_RENDER_WIDGET_HOST_PAINTING_OBSERVER_H_
 #define CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_PAINTING_OBSERVER_H_
 
 class BackingStore;
 class RenderWidgetHost;
 
 // This class can be used to observe painting events for a RenderWidgetHost.
 // Its primary goal in Chrome is to allow thumbnails to be generated.
 class RenderWidgetHostPaintingObserver {
  public:
   // Indicates the RenderWidgetHost is about to destroy the backing store. The
   // backing store will still be valid when this call is made.
   virtual void WidgetWillDestroyBackingStore(RenderWidgetHost* widget,
                                              BackingStore* backing_store) = 0;
 
   // Indicates that the RenderWidgetHost just updated the backing store.
   virtual void WidgetDidUpdateBackingStore(RenderWidgetHost* widget) = 0;
-
- protected:
-  ~RenderWidgetHostPaintingObserver() {}
 };
 
 #endif  // CHROME_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_PAINTING_OBSERVER_H_