Export IceConfig

Despite being in an "internal" header, IceTransportInternal is already
exported and used outside WebRTC. IceConfig is a counterpart to
IceTransportInternal, so they should be either exported or not exported
together.

See
https://chromium-review.googlesource.com/c/chromium/src/+/4980065/comment/a3a77a56_6d6c2c84/

Bug: chromium:1394755, webrtc:15609
Change-Id: I750d0de81da6ad50fade15d8f7cc57b1ca89e4be
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/325220
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Commit-Queue: David Benjamin <davidben@webrtc.org>
Auto-Submit: David Benjamin <davidben@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#41029}
diff --git a/p2p/base/ice_transport_internal.h b/p2p/base/ice_transport_internal.h
index 98deb49..eb21596 100644
--- a/p2p/base/ice_transport_internal.h
+++ b/p2p/base/ice_transport_internal.h
@@ -105,7 +105,9 @@
 // Information about ICE configuration.
 // TODO(deadbeef): Use absl::optional to represent unset values, instead of
 // -1.
-struct IceConfig {
+//
+// TODO(bugs.webrtc.org/15609): Define a public API for this.
+struct RTC_EXPORT IceConfig {
   // The ICE connection receiving timeout value in milliseconds.
   absl::optional<int> receiving_timeout;
   // Time interval in milliseconds to ping a backup connection when the ICE
@@ -234,6 +236,8 @@
 // Once the public interface is supported,
 // (https://www.w3.org/TR/webrtc/#rtcicetransport)
 // the IceTransportInterface will be split from this class.
+//
+// TODO(bugs.webrtc.org/15609): Define a public API for this.
 class RTC_EXPORT IceTransportInternal : public rtc::PacketTransportInternal {
  public:
   IceTransportInternal();