Depending on what you’re trying to do, you might get away with this:
private Set<Account> mAccountCache; // init & populated when the listener is registered
@Override
public void onAccountsUpdated(Account[] accounts) {
// This code assumes we're only interested in removed items.
final Set<Account> currentAccounts = new HashSet<Account>(Arrays.asList(accounts));
final Set<Account> removedAccounts = new HashSet<Account>(mAccountCache);
removedAccounts.removeAll(currentAccounts); // populated with Accounts that were removed.
}