"Screencastify is a simple video screen capture software (aka. screencast recorder) for Chrome. It is able to record all screen activity inside a tab, including audio. Just press record and the content of your tab is recorded. So you can easily create a screencast for video tutorials, record presentations etc. It also supports desktop capturing, allowing you to record anything on your screen (not just tabs)."
Confira "Screencastify (Screen Video Recorder)":