Resize the window to 720p!
Ideal for using ChromeCast: This extension forces the inside of your tab to be 720p! - This means no black bars on the TV you're using. Of course this extension can be used for many other things.
It requires no permissions, cannot read your tabs and the code is easy and clean to read.
Of course, the resizing is not limited to just 720p, you can input any resolution you want! A few basic resolutions are included.