Make IDL Callbacks non-refcounted by default

Source/core/platform/chromium/ChromiumDataObjectItem.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 84 matching lines @@
 }
 
 ChromiumDataObjectItem::ChromiumDataObjectItem(const String& kind, const String& type, uint64_t sequenceNumber)
     : m_source(PasteboardSource)
     , m_kind(kind)
     , m_type(type)
     , m_sequenceNumber(sequenceNumber)
 {
 }
 
-void ChromiumDataObjectItem::getAsString(PassRefPtr<StringCallback> callback, ExecutionContext* context) const
+void ChromiumDataObjectItem::getAsString(PassOwnPtr<StringCallback> callback, ExecutionContext* context) const
 {
     if (!callback || kind() != DataTransferItem::kindString)
         return;
 
-    callback->scheduleCallback(context, internalGetAsString());
+    StringCallback::scheduleCallback(callback, context, internalGetAsString());
 }
 
 PassRefPtr<Blob> ChromiumDataObjectItem::getAsFile() const
 {
     if (kind() != DataTransferItem::kindFile)
         return 0;
 
     if (m_source == InternalSource) {
         if (m_file)
             return m_file;
@@ skipping 53 matching lines @@
 
 bool ChromiumDataObjectItem::isFilename() const
 {
     // FIXME: https://bugs.webkit.org/show_bug.cgi?id=81261: When we properly support File dragout,
     // we'll need to make sure this works as expected for DragDataChromium.
     return m_kind == DataTransferItem::kindFile && m_file;
 }
 
 } // namespace WebCore