Hi Niroshan Madusanka!
Google does not check all uploaded content to see if it's illegal or not.
There can be many causes of someone's actual content be specifically checked, including other users reporting you. Sharing of such content may trigger a check as well.
Google is also governed by the laws of the country you live in. Those laws change from country to country.
In general, if you aren't sure it's safe to store any data in your cloud, you shouldn't take the chance.