This is a basic AclManager service. It only handles ObjectAces. It provides a grant, revoke and revokeAll method.

AclManager.php

<?php

namespace Smoovi\CoreBundle\Security;

use Symfony\Component\Security\Acl\Model\AclProviderInterface,
    Symfony\Component\Security\Acl\Domain\ObjectIdentity,
    Symfony\Component\Security\Acl\Domain\UserSecurityIdentity;

use Smoovi\CoreBundle\Security\Acl\Permission\MaskBuilder;

/**
 * Easily work with Symfony ACL
 *
 * @author Brammm
 */
class AclManager {

    protected $provider;

    /**
     * Constructor
     *
     * @param AclProviderInterface $provider
     */
    public function __construct(AclProviderInterface $provider)
    {
        $this->provider = $provider;
    }

    /**
     * Grants a permission to $user for $object
     * Will check for existing permissions and update accordingly
     *
     * @param $object
     * @param $user
     * @param int $mask
     */
    public function grant($object, $user, $mask = MaskBuilder::MASK_OWNER)
    {
        // Create identities
        $oid = ObjectIdentity::fromDomainObject($object);
        $sid = UserSecurityIdentity::fromAccount($user);

        // Get ACL
        $acl = $this->getAcl($oid);

        // Try to find an ACE for the user
        // If one doesn't exist, insert a new one.
        list($i, $ace) = $this->getAce($acl, $sid);

        if (isset($ace)) {
            // We found an ACE. If the mask's the same, we just stop here
            if ($ace->getMask() == $mask) {
                return;
            }

            $newMask = $ace->getMask() & $mask; // Bitwise operator, adding the masks together
            $acl->updateObjectAce($i, $newMask);
        } else {
            $acl->insertObjectAce($sid, $mask);
        }

        $this->provider->updateAcl($acl);
    }

    /**
     * Revokes a permission to $user for $object
     * Will only revoke the given permission
     *
     * @param $object
     * @param $user
     * @param $mask
     */
    public function revoke($object, $user, $mask)
    {
        // Create identities and get ACL
        $oid = ObjectIdentity::fromDomainObject($object);
        $sid = UserSecurityIdentity::fromAccount($user);
        $acl = $this->getAcl($oid, false);

        // Get the ACE
        list($i, $ace) = $this->getAce($acl, $sid);

        if (isset($ace)) {
            $newMask = $ace->getMask() & ~$mask;
            if ($newMask === 0) {
                $acl->deleteObjectAce($i);
            } else {
                $acl->updateObjectAce($i, $newMask);
            }

            $this->provider->updateAcl($acl);
        }
    }

    /**
     * Revokes all permissions to $user for $object
     *
     * @param $object
     * @param $user
     */
    public function revokeAll($object, $user)
    {
        // Create identities and get ACL
        $oid = ObjectIdentity::fromDomainObject($object);
        $sid = UserSecurityIdentity::fromAccount($user);
        $acl = $this->getAcl($oid, $sid, false);

        // Get the ACE
        list($i, $ace) = $this->getAce($acl, $sid);

        if (isset($ace)) {
            $acl->deleteObjectAce($i);

            $this->provider->updateAcl($acl);
        }
    }

    /**
     * Get an ACL for an object and a user
     * If createEmpty is false, it will throw an error if it can't find the ACL
     *
     * @param $oid
     * @param $sid
     * @param bool $createEmpty
     * @throws \Exception
     * @return \Symfony\Component\Security\Acl\Model\MutableAclInterface
     */
    protected function getAcl($oid, $createEmpty = true)
    {
        // Try to find an existing ACL
        // If one doesn't exist, create one if necessary.
        try {
            return $this->provider->findAcl($oid);
        } catch (\Exception $e) {
            if ($createEmpty) {
                return $this->provider->createAcl($oid);
            } else {
                throw $e;
            }
        }
    }

    /**
     * Gets the user ACE
     * 
     * It returns the index of the ace and the ace itself. We sadly need the index as well.
     * 
     * @param $acl
     * @param $sid
     * @return array
     */
    protected function getAce($acl, $sid)
    {
        $index = $ace = null;
        foreach ($acl->getObjectAces() as $i => $maybeAce) {
            if ($sid->equals($maybeAce->getSecurityIdentity())) {
                $index = $i;
                $ace = $maybeAce;
                break; // stop the loop, we have our ace
            }
        }

        return [$index, $ace];
    }
}

what about that https://gist.github.com/CodingNinja/1539784

I based my own version off off what @CodingNinja did. However, his version kept throwing errors for me, so I wrote my own.