Make ExtensionContentSettingsStore refcounted.

chrome/browser/extensions/extension_prefs.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_EXTENSIONS_EXTENSION_PREFS_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_PREFS_H_
 #pragma once
 
 #include <set>
 #include <string>
@@ skipping 328 matching lines @@
   // For unit testing. Enables injecting an artificial clock that is used
   // to query the current time, when an extension is installed.
   virtual base::Time GetCurrentTime() const;
 
  private:
   // ExtensionContentSettingsStore::Observer methods:
   virtual void OnContentSettingChanged(
       const std::string& extension_id,
       bool incognito) OVERRIDE;
 
-  virtual void OnDestruction() OVERRIDE {}
-
   // Converts absolute paths in the pref to paths relative to the
   // install_directory_.
   void MakePathsRelative();
 
   // Converts internal relative paths to be absolute. Used for export to
   // consumers who expect full paths.
   void MakePathsAbsolute(DictionaryValue* dict);
 
   // Sets the pref |key| for extension |id| to |value|.
   void UpdateExtensionPref(const std::string& id,
@@ skipping 75 matching lines @@
 
   // The pref service specific to this set of extension prefs. Owned by profile.
   PrefService* prefs_;
 
   // Base extensions install directory.
   FilePath install_directory_;
 
   // Weak pointer, owned by Profile.
   ExtensionPrefValueMap* extension_pref_value_map_;
 
-  scoped_ptr<ExtensionContentSettingsStore> content_settings_store_;
+  scoped_refptr<ExtensionContentSettingsStore> content_settings_store_;
 
   // The URLs of all of the toolstrips.
   URLList shelf_order_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionPrefs);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_PREFS_H_