Transparent ChromeOS window

Question

The new hangouts extension from Google is able to make a transparent chrome.app.window somehow. Whilst trying to debug their code I found a lot of clear references to this, but I was not able to figure out how to do this myself. So, how do you make transparent chromeOS windows?

Answer 1

Hangouts is whitelisted to do that on stable. You can try it in dev channel with this demo: https://github.com/beaufortfrancois/bubble-mirror-chrome-app. Here is the design doc: https://docs.google.com/document/d/1BwU__X2WEayBwa2Su0o4FYrGSqlqcC5q8lQigfTCYCI