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

chrome/common/extensions/api/extension_api_unittest.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/common/extensions/api/extension_api.h"
 
 #include <string>
 #include <vector>
 
 #include "base/file_path.h"
@@ skipping 402 matching lines @@
 
     Feature* feature = api.GetFeature("test");
     EXPECT_EQ(test_data[i].expect_success, feature != NULL) << i;
   }
 }
 
 static void GetDictionaryFromList(const DictionaryValue* schema,
                                   const std::string& list_name,
                                   const int list_index,
                                   DictionaryValue** out) {
-  ListValue* list;
+  const ListValue* list;
   EXPECT_TRUE(schema->GetList(list_name, &list));
   EXPECT_TRUE(list->GetDictionary(list_index, out));
 }
 
 TEST(ExtensionAPI, TypesHaveNamespace) {
   FilePath manifest_path;
   PathService::Get(chrome::DIR_TEST_DATA, &manifest_path);
   manifest_path = manifest_path.AppendASCII("extensions")
       .AppendASCII("extension_api_unittest")
       .AppendASCII("types_have_namespace.json");
@@ skipping 46 matching lines @@
   GetDictionaryFromList(dict, "parameters", 0, &sub_dict);
   EXPECT_TRUE(sub_dict->GetString("$ref", &type));
   EXPECT_EQ("test.foo.TestType", type);
   GetDictionaryFromList(dict, "parameters", 1, &sub_dict);
   EXPECT_TRUE(sub_dict->GetString("$ref", &type));
   EXPECT_EQ("fully.qualified.Type", type);
 }
 
 }  // namespace
 }  // namespace extensions