Publish function_video_(en|de)coder_factory into api

Bug: None
Change-Id: Ibdae580c085cfc4b063fdc7f1edb8312de438722
Reviewed-on: https://webrtc-review.googlesource.com/c/107705
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25360}
diff --git a/test/BUILD.gn b/test/BUILD.gn
index dc6dc79..8ba4ec5 100644
--- a/test/BUILD.gn
+++ b/test/BUILD.gn
@@ -662,6 +662,7 @@
     "../api:transport_api",
     "../api/audio_codecs:builtin_audio_decoder_factory",
     "../api/audio_codecs:builtin_audio_encoder_factory",
+    "../api/test/video:function_video_factory",
     "../api/video:video_frame",
     "../api/video_codecs:video_codecs_api",
     "../audio",