Replace RegisterExternalDecoder with decoder factory in NetEqImplTest120ms

Change-Id: I86b5f748f556be186f020a97fcc1211f953fd219

Bug: webrtc:10080
Change-Id: I86b5f748f556be186f020a97fcc1211f953fd219
Reviewed-on: https://webrtc-review.googlesource.com/c/112600
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Niels Moller <nisse@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25869}
diff --git a/test/BUILD.gn b/test/BUILD.gn
index 70e53f5..1557af2 100644
--- a/test/BUILD.gn
+++ b/test/BUILD.gn
@@ -830,6 +830,7 @@
 rtc_source_set("audio_codec_mocks") {
   testonly = true
   sources = [
+    "function_audio_decoder_factory.h",
     "mock_audio_decoder.cc",
     "mock_audio_decoder.h",
     "mock_audio_decoder_factory.h",
@@ -843,7 +844,9 @@
     "../api:array_view",
     "../api/audio_codecs:audio_codecs_api",
     "../api/audio_codecs:builtin_audio_decoder_factory",
+    "../rtc_base:checks",
     "../rtc_base:rtc_base_approved",
+    "//third_party/abseil-cpp/absl/memory",
   ]
 }