Correct const accessors in base/values.(h|cc), Part II (ListValue)

ash/system/network/tray_sms.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 "ash/system/network/tray_sms.h"
 
 #include "ash/ash_switches.h"
 #include "ash/shell.h"
 #include "ash/system/tray/system_tray.h"
 #include "ash/system/tray/tray_constants.h"
@@ skipping 191 matching lines @@
     if (preferred_size.height() < kMessageListMinHeight)
       preferred_size.set_height(kMessageListMinHeight);
     return preferred_size;
   }
 
  private:
   void UpdateMessageList() {
     const base::ListValue& messages = tray_->messages();
     scroll_content()->RemoveAllChildViews(true);
     for (size_t index = 0; index < messages.GetSize(); ++index) {
-      base::DictionaryValue* message = NULL;
+      const base::DictionaryValue* message = NULL;
       if (!messages.GetDictionary(index, &message)) {
         LOG(ERROR) << "SMS message not a dictionary at: " << index;
         continue;
       }
       std::string number, text;
       if (!GetMessageFromDictionary(message, &number, &text)) {
         LOG(ERROR) << "Error parsing SMS message";
         continue;
       }
       SmsMessageView* msgview = new SmsMessageView(
@@ skipping 146 matching lines @@
       if (GetLatestMessage(&index, &number, &text))
         notification_->Update(index, number, text);
     } else if (notify) {
       ShowNotificationView();
     }
   }
 }
 
 }  // namespace internal
 }  // namespace ash