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

sync/internal_api/public/change_record_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 "sync/internal_api/public/change_record.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "base/string_number_conversions.h"
 #include "base/test/values_test_util.h"
 #include "base/values.h"
@@ skipping 37 matching lines @@
 void CheckChangeRecordValue(
     const ChangeRecord& record,
     const base::DictionaryValue& value) {
   ExpectChangeRecordActionValue(record.action, value, "action");
   ExpectDictStringValue(base::Int64ToString(record.id), value, "id");
   if (record.action == ChangeRecord::ACTION_DELETE) {
     scoped_ptr<base::DictionaryValue> expected_extra_value;
     if (record.extra.get()) {
       expected_extra_value.reset(record.extra->ToValue());
     }
-    base::Value* extra_value = NULL;
+    const base::Value* extra_value = NULL;
     EXPECT_EQ(record.extra.get() != NULL,
               value.Get("extra", &extra_value));
     EXPECT_TRUE(Value::Equals(extra_value, expected_extra_value.get()));
 
     scoped_ptr<DictionaryValue> expected_specifics_value(
         EntitySpecificsToValue(record.specifics));
     ExpectDictDictionaryValue(*expected_specifics_value,
                               value, "specifics");
   }
 }
@@ skipping 59 matching lines @@
         Invoke(&extra_value, &DictionaryValue::DeepCopy));
 
     record.extra.reset(extra.release());
     scoped_ptr<DictionaryValue> value(record.ToValue());
     CheckChangeRecordValue(record, *value);
   }
 }
 
 }  // namespace
 }  // namespace syncer