Force encryption migration if the device supports ARC.

chromeos/cryptohome/homedir_methods.cc

Index: chromeos/cryptohome/homedir_methods.cc
diff --git a/chromeos/cryptohome/homedir_methods.cc b/chromeos/cryptohome/homedir_methods.cc
index 1b540eb06050b32d0967f38e85be7aa775f5bca9..feda3ee8c453d84e123480a4857836db34a56968 100644
--- a/chromeos/cryptohome/homedir_methods.cc
+++ b/chromeos/cryptohome/homedir_methods.cc
@@ -224,6 +224,9 @@ class HomedirMethodsImpl : public HomedirMethods {
         FillKeyProtobuf(request.create_keys[i], create->add_keys());
     }
 
+    if (request.force_dircrypto_if_available)
+      request_proto.set_force_dircrypto_if_available(true);
+
     DBusThreadManager::Get()->GetCryptohomeClient()->MountEx(
         id, auth_proto, request_proto,
         base::Bind(&HomedirMethodsImpl::OnMountExCallback,