diff --git a/metrics.h b/metrics.h
index 330e0de..58a7eaf 100644
--- a/metrics.h
+++ b/metrics.h
@@ -195,6 +195,12 @@
     kTerminationActionReasonTerminate
   };
 
+  enum Cellular3GPPRegistrationDelayedDrop {
+    kCellular3GPPRegistrationDelayedDropPosted = 0,
+    kCellular3GPPRegistrationDelayedDropCanceled = 1,
+    kCellular3GPPRegistrationDelayedDropMax
+  };
+
   enum CellularDropTechnology {
     kCellularDropTechnology1Xrtt = 0,
     kCellularDropTechnologyEdge = 1,
@@ -367,6 +373,7 @@
   static const char kMetricServiceFixupEntries[];
 
   // Cellular specific statistics.
+  static const char kMetricCellular3GPPRegistrationDelayedDrop[];
   static const char kMetricCellularAutoConnectTries[];
   static const int kMetricCellularAutoConnectTriesMax;
   static const int kMetricCellularAutoConnectTriesMin;
@@ -539,6 +546,10 @@
                                 const std::string &network_technology,
                                 uint16 signal_strength);
 
+  // Notifies this object about 3GPP registration drop events.
+  virtual void Notify3GPPRegistrationDelayedDropPosted();
+  virtual void Notify3GPPRegistrationDelayedDropCanceled();
+
   // Notifies this object about a cellular device failure code.
   void NotifyCellularDeviceFailure(const Error &error);