A Web Whiteboard is not technically a Chrome app. It is a web app with touch screen capabilities.
One nice feature in the recent version of Chrome OS is the ability to treat web apps like this as a regular Chrome App.
In the video I show how in settings, more tools, you can add any site to your shelf.
I really like AWW. It is very basic which is great because in whiteboard, especially on a touch screen, you don't want a lot of tools getting in your way.
Basically, what you get is the ability to change pen color and size. If needed, you can insert a picture, photo, or text. I love the ability to use a touch screen capable web app on any device including smart phone, tablet, and Chromebook.