NetEq: Drop unnecessary dependency on the audio decoder implementations

BUG=webrtc:8396

Change-Id: I7524dae93b43b656a13fdd535e48373bc29b405e
Reviewed-on: https://webrtc-review.googlesource.com/10804
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#20310}
diff --git a/modules/audio_coding/neteq/include/neteq.h b/modules/audio_coding/neteq/include/neteq.h
index e6cafa8..d66a3ea 100644
--- a/modules/audio_coding/neteq/include/neteq.h
+++ b/modules/audio_coding/neteq/include/neteq.h
@@ -16,9 +16,10 @@
 #include <string>
 #include <vector>
 
+#include "api/audio_codecs/audio_decoder.h"
 #include "api/optional.h"
 #include "common_types.h"  // NOLINT(build/include)
-#include "modules/audio_coding/neteq/audio_decoder_impl.h"
+#include "modules/audio_coding/neteq/neteq_decoder_enum.h"
 #include "rtc_base/constructormagic.h"
 #include "rtc_base/scoped_ref_ptr.h"
 #include "typedefs.h"  // NOLINT(build/include)