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

base/json/json_writer.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 "base/json/json_writer.h"
 
 #include <cmath>
 
 #include "base/json/string_escape.h"
 #include "base/logging.h"
@@ skipping 155 matching lines @@
       {
         json_string_->append("{");
         if (pretty_print_)
           json_string_->append(kPrettyPrintLineEnding);
 
         const DictionaryValue* dict =
           static_cast<const DictionaryValue*>(node);
         for (DictionaryValue::key_iterator key_itr = dict->begin_keys();
              key_itr != dict->end_keys();
              ++key_itr) {
-          Value* value = NULL;
+          const Value* value = NULL;
           bool result = dict->GetWithoutPathExpansion(*key_itr, &value);
           DCHECK(result);
 
           if (omit_binary_values_ && value->GetType() == Value::TYPE_BINARY) {
             continue;
           }
 
           if (key_itr != dict->begin_keys()) {
             json_string_->append(",");
             if (pretty_print_)
@@ skipping 40 matching lines @@
   JsonDoubleQuote(UTF8ToUTF16(str), true, json_string_);
 }
 
 void JSONWriter::IndentLine(int depth) {
   // It may be faster to keep an indent string so we don't have to keep
   // reallocating.
   json_string_->append(std::string(depth * 3, ' '));
 }
 
 }  // namespace base