vold: Do not cache CE keys in vold

CE keys were cached in vold to support untrusted reset
by a device admin, this is now supported by Locksettingservice
using synthetic password. This change requires a secret to be
provided to retrieve the CE key and re-wrap without the secret
when user removes the credential.

Test: Set credential, remove credential, swipe to none
and vice-versa.
Bug: 26948053
Merged-In: I4cb1c035a472477e70c1ff5bf0b2c3fcfad495e5
Change-Id: I4cb1c035a472477e70c1ff5bf0b2c3fcfad495e5
diff --git a/FsCrypt.h b/FsCrypt.h
index 03ec2e1..641991a 100644
--- a/FsCrypt.h
+++ b/FsCrypt.h
@@ -25,6 +25,8 @@
 bool fscrypt_destroy_user_key(userid_t user_id);
 bool fscrypt_add_user_key_auth(userid_t user_id, int serial, const std::string& token,
                                const std::string& secret);
+bool fscrypt_clear_user_key_auth(userid_t user_id, int serial, const std::string& token,
+                                 const std::string& secret);
 bool fscrypt_fixate_newest_user_key_auth(userid_t user_id);
 
 bool fscrypt_unlock_user_key(userid_t user_id, int serial, const std::string& token,