Orator's domReader does not properly selfVoice and highlight content in Chrome

While the domReader doesn't work properly, the selection reader doesn't appear to have any issues with playback.

Steps to reproduce:

1. Open the Prefs framework demo
2. Open the prefs editor
3. Enable text-to-speech
4. In the Orator widget click the play button
5. Notice that the play button turns into a pause button but nothing is self voiced

1. Open the Orator demo
2. Click the play button
3. Notice that the content is self voiced but the word highlighting doesn't appear