Google Slides. The answer is yes, but it's not as straight-forward as you would hope it would be. To add music to Google Slides you first need to find a YouTube video that contains music that is Creative Commons licensed. The best option, is to use a video that you own and that has music you have the rights to use. Once you've found a video then you can insert it into your Google Slides. Shrink the video to the smallest possible size so that it's hard for viewers to see. Finally, use the video options menu in Google Slides to have the music video automatically start playing when you advance the slide.
In the video embedded below I demonstrate how to add music to Google Slides.
This topic and many like it will be covered in depth at the Practical Ed Tech Chromebook Camp on July 20th and 21st. Early registration discounts are still available.