It appears this is being addressed here:
For now, here is one work around to this problem:
1. Quit your Chrome entirely (cmd+Q).
2. Open your Facetime app and leave it open.
3. Open Google Chrome.
4. Start your Hangout.
5. You can now close Facetime app if you want.
You can browse the rest of the thread for more help. I hope a more pernament fix comes soon.