Starting with Chrome 56 on Debian you might end up having no Extensions. To re-enable them again you have to start Chrome with

--enable-remote-extensions

To make this a default add this flag to the default flags in /etc/chromium.d/default-flags:

# Enable extensions
export CHROMIUM_FLAGS="$CHROMIUM_FLAGS --enable-remote-extensions"

Reference: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=851927