am 2450173b: Merge change 5414 into donut

Merge commit '2450173b78b27ca744e5d2e58efa35560ce73f8c'

* commit '2450173b78b27ca744e5d2e58efa35560ce73f8c':
  Add caching of the speech rate and language in android.speech.tts.TextToSpeech