message: Using nullopt when connection is nullptr.
  During SelectConnectionToPing, optional connection had the value of nullptr which led the code to crash.
  Cr-Commit-Position: refs/heads/master@{#33197}
diff: @@ -87,7 +87,9 @@ class IceControllerInterface {
  // This represents the result of a call to SelectConnectionToPing.
  struct PingResult {
  PingResult(const Connection* conn, int _recheck_delay_ms)
  - : connection(conn), recheck_delay_ms(_recheck_delay_ms) {}
  + : connection(conn ? absl::optional<const Connection*>(conn)
  + : absl::nullopt),
  + recheck_delay_ms(_recheck_delay_ms) {}
  // Connection that we should (optionally) ping.
  const absl::optional<const Connection*> connection;
  