Correct const accessors in base/values.(h|cc)

chrome/browser/extensions/extension_prefs.h

 // Copyright (c) 2012 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_
 
 #include <set>
 #include <string>
 #include <vector>
@@ skipping 508 matching lines @@
   const base::DictionaryValue* GetExtensionPref(const std::string& id) const;
 
   // Loads the preferences controlled by the specified extension from their
   // dictionary and sets them in the |pref_value_map_|.
   void LoadExtensionControlledPrefs(const std::string& id,
                                     ExtensionPrefsScope scope);
 
   // Checks if kPrefBlacklist is set to true in the DictionaryValue.
   // Return false if the value is false or kPrefBlacklist does not exist.
   // This is used to decide if an extension is blacklisted.
-  static bool IsBlacklistBitSet(base::DictionaryValue* ext);
+  static bool IsBlacklistBitSet(const base::DictionaryValue* ext);
 
   // Fix missing preference entries in the extensions that are were introduced
   // in a later Chrome version.
   void FixMissingPrefs(const ExtensionIdSet& extension_ids);
 
   // Installs the persistent extension preferences into |prefs_|'s extension
   // pref store. Does nothing if |extensions_disabled| is true.
   void InitPrefStore(bool extensions_disabled);
 
   // Migrates the permissions data in the pref store.
@@ skipping 18 matching lines @@
   scoped_ptr<ExtensionSorting> extension_sorting_;
 
   scoped_refptr<ContentSettingsStore> content_settings_store_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionPrefs);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_PREFS_H_