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

chrome/browser/extensions/api/commands/command_service.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/extensions/api/commands/command_service.h"
 
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/extensions/extension_keybinding_registry.h"
 #include "chrome/browser/extensions/extension_service.h"
@@ skipping 152 matching lines @@
   ui::Accelerator accelerator = Command::StringToAccelerator(keystroke);
   AddKeybindingPref(accelerator, extension_id, command_name, true);
 }
 
 ui::Accelerator CommandService::FindShortcutForCommand(
     const std::string& extension_id, const std::string& command) {
   const DictionaryValue* bindings =
       profile_->GetPrefs()->GetDictionary(prefs::kExtensionKeybindings);
   for (DictionaryValue::key_iterator it = bindings->begin_keys();
        it != bindings->end_keys(); ++it) {
-    DictionaryValue* item = NULL;
+    const DictionaryValue* item = NULL;
     bindings->GetDictionary(*it, &item);
 
     std::string extension;
     item->GetString(kExtension, &extension);
     if (extension != extension_id)
       continue;
     std::string command_name;
     item->GetString(kCommandName, &command_name);
     if (command != command_name)
       continue;
@@ skipping 112 matching lines @@
     return false;
 
   *command = *requested_command;
   if (shortcut_assigned.key_code() != ui::VKEY_UNKNOWN)
     command->set_accelerator(shortcut_assigned);
 
   return true;
 }
 
 }  // namespace extensions