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

chrome/common/extensions/extension_message_bundle.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/extension_message_bundle.h"
 
 #include <string>
 #include <vector>
 
 #include "base/hash_tables.h"
@@ skipping 116 matching lines @@
   }
 
   return true;
 }
 
 bool ExtensionMessageBundle::GetMessageValue(const std::string& key,
                                              const DictionaryValue& catalog,
                                              std::string* value,
                                              std::string* error) const {
   // Get the top level tree for given key (name part).
-  DictionaryValue* name_tree;
+  const DictionaryValue* name_tree;
   if (!catalog.GetDictionaryWithoutPathExpansion(key, &name_tree)) {
     *error = base::StringPrintf("Not a valid tree for key %s.", key.c_str());
     return false;
   }
   // Extract message from it.
   if (!name_tree->GetString(kMessageKey, value)) {
     *error = base::StringPrintf(
         "There is no \"%s\" element for key %s.", kMessageKey, key.c_str());
     return false;
   }
@@ skipping 11 matching lines @@
 ExtensionMessageBundle::ExtensionMessageBundle() {
 }
 
 bool ExtensionMessageBundle::GetPlaceholders(const DictionaryValue& name_tree,
                                              const std::string& name_key,
                                              SubstitutionMap* placeholders,
                                              std::string* error) const {
   if (!name_tree.HasKey(kPlaceholdersKey))
     return true;
 
-  DictionaryValue* placeholders_tree;
+  const DictionaryValue* placeholders_tree;
   if (!name_tree.GetDictionary(kPlaceholdersKey, &placeholders_tree)) {
     *error = base::StringPrintf("Not a valid \"%s\" element for key %s.",
                                 kPlaceholdersKey, name_key.c_str());
     return false;
   }
 
   for (DictionaryValue::key_iterator key_it = placeholders_tree->begin_keys();
        key_it != placeholders_tree->end_keys(); ++key_it) {
-    DictionaryValue* placeholder;
+    const DictionaryValue* placeholder;
     const std::string& content_key(*key_it);
     if (!IsValidName(content_key))
       return BadKeyMessage(content_key, error);
     if (!placeholders_tree->GetDictionaryWithoutPathExpansion(content_key,
                                                               &placeholder)) {
       *error = base::StringPrintf("Invalid placeholder %s for key %s",
                                   content_key.c_str(),
                                   name_key.c_str());
       return false;
     }
@@ skipping 148 matching lines @@
 }
 
 L10nMessagesMap* GetL10nMessagesMap(const std::string& extension_id) {
   ExtensionToL10nMessagesMap::iterator it =
       g_extension_to_messages_map.Get().messages_map.find(extension_id);
   if (it != g_extension_to_messages_map.Get().messages_map.end())
     return &(it->second);
 
   return NULL;
 }