diff --git a/common/constants.cc b/common/constants.cc
index d779dd4..58cf1b3 100644
--- a/common/constants.cc
+++ b/common/constants.cc
@@ -18,6 +18,9 @@
 
 namespace chromeos_update_engine {
 
+// Keep this in sync with the one in dlcservice.
+const char kDlcMetadataRootpath[] = "/var/lib/dlc/";
+
 const char kPowerwashSafePrefsSubDirectory[] = "update_engine/prefs";
 
 const char kPrefsSubDirectory[] = "prefs";
@@ -60,6 +63,11 @@
 const char kPrefsP2PFirstAttemptTimestamp[] = "p2p-first-attempt-timestamp";
 const char kPrefsP2PNumAttempts[] = "p2p-num-attempts";
 const char kPrefsPayloadAttemptNumber[] = "payload-attempt-number";
+// Keep |kPrefsPingActive| in sync with |kDlcMetadataFilePingActive| in
+// dlcservice.
+const char kPrefsPingActive[] = "active";
+const char kPrefsPingLastActive[] = "date_last_active";
+const char kPrefsPingLastRollcall[] = "date_last_rollcall";
 const char kPrefsPostInstallSucceeded[] = "post-install-succeeded";
 const char kPrefsPreviousVersion[] = "previous-version";
 const char kPrefsResumedUpdateFailures[] = "resumed-update-failures";