Make AudioFrameType an enum class, and move to audio_coding_module_typedefs.h

Bug: webrtc:5876
Change-Id: I0c92f9410fcf0832bfa321229b3437134255dba6
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/128085
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27190}
diff --git a/modules/audio_coding/acm2/acm_send_test.cc b/modules/audio_coding/acm2/acm_send_test.cc
index 4c34e41..c558f7b 100644
--- a/modules/audio_coding/acm2/acm_send_test.cc
+++ b/modules/audio_coding/acm2/acm_send_test.cc
@@ -44,7 +44,7 @@
           static_cast<size_t>(source_rate_hz_ * kBlockSizeMs / 1000)),
       codec_registered_(false),
       test_duration_ms_(test_duration_ms),
-      frame_type_(kAudioFrameSpeech),
+      frame_type_(AudioFrameType::kAudioFrameSpeech),
       payload_type_(0),
       timestamp_(0),
       sequence_number_(0) {