Bug 1388288 - Make OpusTrackEncoder build in non-Unified mode. r=SingingTree

MozReview-Commit-ID: 9Y6rkxYwVhw

--HG--
extra : rebase_source : 5d5f61b9cd83ac13c2c328a22bf033b9ad3ab4c4

dom/media/encoder/OpusTrackEncoder.cpp

@@ -6,6 +6,7 @@
 #include "nsString.h"
 #include "GeckoProfiler.h"
 #include "mozilla/CheckedInt.h"
+#include "VideoUtils.h"
 
 #include <opus/opus.h>