Add a mount with metadata encryption service

Don't use the FDE flow to support metadata encryption; just provide a
vold service which directly mounts the volume and use that.

Bug: 63927601
Test: Boot Taimen to SUW with and without metadata encryption.
Change-Id: Ifc6a012c02c0ea66893020ed1d0da4cba6914aed
diff --git a/MetadataCrypt.h b/MetadataCrypt.h
index f6634ea..841dc97 100644
--- a/MetadataCrypt.h
+++ b/MetadataCrypt.h
@@ -17,7 +17,8 @@
 #ifndef _METADATA_CRYPT_H
 #define _METADATA_CRYPT_H
 
-bool e4crypt_mount_metadata_encrypted();
-bool e4crypt_enable_crypto();
+#include <string>
+
+bool e4crypt_mount_metadata_encrypted(const std::string& mount_point, bool needs_encrypt);
 
 #endif