Merge change 7913 into donut

* changes:
  Reorganize message posting when updating sizes and resources. Rather than posting a message for each package, post a message for  a set of packages(8) so that we don't end up posting too many messages and making the UI non-responsive by keeping the Handler too busy. We just pass the loaded info as a map in the message object. Changes to back ground threads that compute sizes and load resources.