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

chrome/installer/util/master_preferences.cc

 // 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.
 
 #include "chrome/installer/util/master_preferences.h"
 
 #include "base/environment.h"
 #include "base/file_util.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/lazy_instance.h"
@@ skipping 21 matching lines @@
   GURL gurl(url);
   *out_value = gurl;
   return true;
 }
 
 std::vector<GURL> GetNamedList(const char* name,
                                const DictionaryValue* prefs) {
   std::vector<GURL> list;
   if (!prefs)
     return list;
-  ListValue* value_list = NULL;
+  const ListValue* value_list = NULL;
   if (!prefs->GetList(name, &value_list))
     return list;
   for (size_t i = 0; i < value_list->GetSize(); ++i) {
     Value* entry;
     GURL gurl_entry;
     if (!value_list->Get(i, &entry) || !GetGURLFromValue(entry, &gurl_entry)) {
       NOTREACHED();
       break;
     }
     list.push_back(gurl_entry);
@@ skipping 212 matching lines @@
 bool MasterPreferences::GetExtensionsBlock(DictionaryValue** extensions) const {
   return master_dictionary_->GetDictionary(
       master_preferences::kExtensionsBlock, extensions);
 }
 
 // static
 const MasterPreferences& MasterPreferences::ForCurrentProcess() {
   return g_master_preferences.Get();
 }
 }  // installer_util