system_api: extend ArcDataSnapshotd d-bus interface

BUG=b:160387490
TEST=compile

Change-Id: Iab979a3171472180933d9424a5cff3b84a9afcd8
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/2543148
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Polina Bondarenko <pbond@chromium.org>
Tested-by: Polina Bondarenko <pbond@chromium.org>
Auto-Submit: Polina Bondarenko <pbond@chromium.org>
diff --git a/system_api/dbus/arc-data-snapshotd/dbus-constants.h b/system_api/dbus/arc-data-snapshotd/dbus-constants.h
index 997b094..2b8f4b4 100644
--- a/system_api/dbus/arc-data-snapshotd/dbus-constants.h
+++ b/system_api/dbus/arc-data-snapshotd/dbus-constants.h
@@ -19,6 +19,10 @@
 
 // Methods:
 constexpr char kGenerateKeyPairMethod[] = "GenerateKeyPair";
+constexpr char kClearSnapshotMethod[] = "ClearSnapshot";
+constexpr char kTakeSnapshotMethod[] = "TakeSnapshot";
+constexpr char kLoadSnapshotMethod[] = "LoadSnapshot";
+constexpr char kUpdateMethod[] = "Update";
 
 }  // namespace data_snapshotd
 }  // namespace arc