Two phases to set the password for disk encryption

In one phase, we make the new password work, and in the second we make
it the only one which works ("fixation"). This means that we can set
the password in Gatekeeper between these two phases, and a crash
doesn't break things. Unlocking a user automatically fixates the
presented credential.

Bug: 28154455
Change-Id: I54623c8652f0c9f72dd60388a7dc0ab2d48e81c7
diff --git a/Ext4Crypt.h b/Ext4Crypt.h
index 89cfbab..2dcc197 100644
--- a/Ext4Crypt.h
+++ b/Ext4Crypt.h
@@ -28,8 +28,9 @@
 bool e4crypt_init_user0();
 bool e4crypt_vold_create_user_key(userid_t user_id, int serial, bool ephemeral);
 bool e4crypt_destroy_user_key(userid_t user_id);
-bool e4crypt_change_user_key(userid_t user_id, int serial, const char* token,
-                             const char* old_secret, const char* new_secret);
+bool e4crypt_add_user_key_auth(userid_t user_id, int serial, const char* token,
+                               const char* secret);
+bool e4crypt_fixate_newest_user_key_auth(userid_t user_id);
 
 bool e4crypt_unlock_user_key(userid_t user_id, int serial, const char* token, const char* secret);
 bool e4crypt_lock_user_key(userid_t user_id);