Revert "Fix a ton of compiler warnings."

app/table_model_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 APP_TABLE_MODEL_OBSERVER_H_
 #define APP_TABLE_MODEL_OBSERVER_H_
 
 // Observer for a TableModel. Anytime the model changes, it must notify its
 // observer.
 class TableModelObserver {
  public:
   // Invoked when the model has been completely changed.
   virtual void OnModelChanged() = 0;
 
   // Invoked when a range of items has changed.
   virtual void OnItemsChanged(int start, int length) = 0;
 
   // Invoked when new items are added.
   virtual void OnItemsAdded(int start, int length) = 0;
 
   // Invoked when a range of items has been removed.
   virtual void OnItemsRemoved(int start, int length) = 0;
-
- protected:
-  ~TableModelObserver() {}
 };
 
 #endif  // APP_TABLE_MODEL_OBSERVER_H_