Flesh out the content settings exceptions lists a bit more.

chrome/browser/dom_ui/content_settings_handler.h

 // Copyright (c) 2010 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_DOM_UI_CONTENT_SETTINGS_HANDLER_H_
 #define CHROME_BROWSER_DOM_UI_CONTENT_SETTINGS_HANDLER_H_
 #pragma once
 
 #include "chrome/browser/dom_ui/options_ui.h"
+#include "chrome/common/notification_observer.h"
+#include "chrome/common/notification_registrar.h"
 
 class ContentSettingsHandler : public OptionsPageUIHandler {
  public:
   ContentSettingsHandler();
   virtual ~ContentSettingsHandler();
 
   // OptionsUIHandler implementation.
   virtual void GetLocalizedValues(DictionaryValue* localized_strings);
 
   virtual void Initialize();
 
   virtual void RegisterMessages();
 
+  // NotificationObserver implementation.
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
+
  private:
   void UpdateImagesExceptionsViewFromModel();
   void SetContentFilter(const Value* value);
   void SetAllowThirdPartyCookies(const Value* value);
+  void RemoveExceptions(const Value* value);
+
+  NotificationRegistrar notification_registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentSettingsHandler);
 };
 
 #endif  // CHROME_BROWSER_DOM_UI_CONTENT_SETTINGS_HANDLER_H_