As of Friday March 12th, Google has released another Android update. While devices usually update automatically, you can always double check by following the steps in the document linked below. Often this is one of the first things that may cause your microphone and/or camera to stop working.
Another thing to check is that your chromebook does not have a lot of uneccesary internet history saved on it.
Simply Press Control + Shift + Backspace on your keyboard.
When the history menu pops up, change the drop down box to "all time" and then clear your history.