Is the langauge of (descriptions of) DFAs that accept $\Sigma^*$ decidable? Is $L = \{\langle A\rangle\mid A\text{ is a DFA and }L(A) = \Sigma^*\}$ decidable?

I know that $L'=\{\langle A,w\rangle \mid A\text{ is a DFA and }w\in L(A)\}$ is decidable, but I'm not sure if this is related.
It's decidable. Think about what an DFA's accepting states must look like if it accepts every possible string. That property is very easy to check.