[GCM] Track connection failures properly

google_apis/gcm/engine/connection_factory.h

Index: google_apis/gcm/engine/connection_factory.h
diff --git a/google_apis/gcm/engine/connection_factory.h b/google_apis/gcm/engine/connection_factory.h
index 962a79a73e200a954881f1692ea96a1cd2a53827..298bf5e423787ecf6f3851b9d16d8196c1c29235 100644
--- a/google_apis/gcm/engine/connection_factory.h
+++ b/google_apis/gcm/engine/connection_factory.h
@@ -23,6 +23,18 @@ class GCM_EXPORT ConnectionFactory {
   typedef base::Callback<void(mcs_proto::LoginRequest* login_request)>
       BuildLoginRequestCallback;
 
+  // Reasons for triggering a connection reset. Note that these enums are
+  // consumed by a histogram, so ordering should not be modified.
+  enum ConnectionResetReason {
+    LOGIN_FAILURE,      // Login response included an error.
+    CLOSE_COMMAND,      // Received a close command.
+    HEARTBEAT_FAILURE,  // Heartbeat was not acknowledged in time.
+    SOCKET_FAILURE,     // net::Socket error.
+    // Count of total number of connection reset reasons. All new reset reasons
+    // should be added above this line.
+    CONNECTION_RESET_COUNT,
+  };
+
   ConnectionFactory();
   virtual ~ConnectionFactory();
 
@@ -62,7 +74,7 @@ class GCM_EXPORT ConnectionFactory {
   // event forced a reset (e.g. server sends a close connection response).
   // If the last connection was made within kConnectionResetWindowSecs, the old
   // backoff is restored, else a new backoff kicks off.
-  virtual void SignalConnectionReset() = 0;
+  virtual void SignalConnectionReset(ConnectionResetReason reason) = 0;
 };
 
 }  // namespace gcm