sanitize
Returns a ColorStateList that is safe to pass to .
If given a null ColorStateList, this will return a new transparent ColorStateList since RippleDrawable requires a non-null ColorStateList.
If given a non-null ColorStateList, this method will log a warning for API 22-27 if the ColorStateList is transparent in the default state and non-transparent in the pressed state. This will result in using the pressed state color for the ripple until the finger is lifted at which point the ripple will transition to the default state color (transparent), making the ripple appear to terminate prematurely.