This example uses the undocumented control strip API and Native Messaging to create content that is specific to a website (in this case, YouTube).
To install, build the Application in Xcode then run:
sudo cp ./Touch\ Bar\ for\ Browser /Applications/
sudo cp ./com.ian.touchbar.json /Library/Google/Chrome/NativeMessagingHosts/
then add the "Chrome-Extension" directory as an extension in Google Chrome.