Merge changes Idf64b96b,Ie717089d into nyc-dev
am: c52269542a

* commit 'c52269542a652250c011018f602d1db346f6cd68':
  Base isDexOptNeeded result on OatFileAssistant::IsUpToDate.
  Only compile dex files if they are not up to date.

Change-Id: Ie20c820d8339bdd2c79d2a6dbe9e5b3ef7192f3b