Regarding fixing inverted/flipped laptop webcam video in Chrome/Chromium based browsers - V4L1 will not work with Chrome. V4L2 is needed for WebRTC video.
A few days ago I updated ASUS P52F laptop to Linux Mint 18 XFCE that is on par with Ubuntu 16.04.1 now. I faced "upside down" webcam video on hangouts and facebook using Chrome web browser only. Firefox works fine. Cheese also displays video properly.
After some googling I found this bug report. In the comment 22 you can see that 2 years ago there was a 0001-Use-libv4l2-for-Linux-V4L-grabber.patch proposed that fixes Chrome/Chromium behavior. For more then a year now libv4l2 is added to Chromium, but is not enabled for Linux. You can see the whole discussion in the bug report thread. Long story short it looks like they are not actively working on fixing this for almost a year now. However, there is some ugly workaround...
You can add Flip this extension to Chrome. It allows you to flip your webcam video or any other element of a webpage. It will flip it only locally, so people who you talk to via Chrome also need to use the same trick. It's not pretty, but it's working... well, kind of ; )
After all switching to Firefox may be a better and more comfortable solution as it looks like webcam video can't be permanently flipped "upside down" with Chrome until Google fix their Linux version. Firefox worked for me in LM18 without any additional hassle. I hope it will work for you as well.