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

chrome/browser/prefs/pref_model_associator.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/browser/prefs/pref_model_associator.h"
 
 #include "base/auto_reset.h"
 #include "base/json/json_reader.h"
 #include "base/json/json_string_value_serializer.h"
 #include "base/location.h"
@@ skipping 236 matching lines @@
   DCHECK_EQ(from_value.GetType(), Value::TYPE_DICTIONARY);
   DCHECK_EQ(to_value.GetType(), Value::TYPE_DICTIONARY);
   const DictionaryValue& from_dict_value =
       static_cast<const DictionaryValue&>(from_value);
   const DictionaryValue& to_dict_value =
       static_cast<const DictionaryValue&>(to_value);
   DictionaryValue* result = to_dict_value.DeepCopy();
 
   for (DictionaryValue::key_iterator key = from_dict_value.begin_keys();
        key != from_dict_value.end_keys(); ++key) {
-    Value* from_value;
+    const Value* from_value;
     bool success = from_dict_value.GetWithoutPathExpansion(*key, &from_value);
     DCHECK(success);
 
     Value* to_key_value;
     if (result->GetWithoutPathExpansion(*key, &to_key_value)) {
       if (to_key_value->GetType() == Value::TYPE_DICTIONARY) {
         Value* merged_value = MergeDictionaryValues(*from_value, *to_key_value);
         result->SetWithoutPathExpansion(*key, merged_value);
       }
       // Note that for all other types we want to preserve the "to"
@@ skipping 170 matching lines @@
   }
 
   syncer::SyncError error =
       sync_processor_->ProcessSyncChanges(FROM_HERE, changes);
 }
 
 void PrefModelAssociator::SetPrefService(PrefService* pref_service) {
   DCHECK(pref_service_ == NULL);
   pref_service_ = pref_service;
 }