Just methods where adding "static" to the declaration was enough, I
didn't do anything with providers that used $this.
Initially by search and replace. There were many mistakes which I
found mostly by running the PHPStorm inspection which searches for
$this usage in a static method. Later I used the PHPStorm "make static"
action which avoids the more obvious mistakes.
Bug: T332865
Change-Id: I47ed6692945607dfa5c139d42edbd934fa4f3a36
