Adopt absl::string_view in modules/audio_coding/

Bug: webrtc:13579
Change-Id: Ifec66fb6ba9724d18539de7245a358c2d13c7939
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/268547
Reviewed-by: Ivo Creusen <ivoc@webrtc.org>
Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org>
Commit-Queue: Ali Tofigh <alito@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#37573}
diff --git a/modules/audio_coding/test/RTPFile.h b/modules/audio_coding/test/RTPFile.h
index a9f574b..b796491 100644
--- a/modules/audio_coding/test/RTPFile.h
+++ b/modules/audio_coding/test/RTPFile.h
@@ -15,6 +15,7 @@
 
 #include <queue>
 
+#include "absl/strings/string_view.h"
 #include "api/rtp_headers.h"
 #include "rtc_base/synchronization/mutex.h"
 #include "rtc_base/thread_annotations.h"
@@ -100,7 +101,7 @@
 
   RTPFile() : _rtpFile(NULL), _rtpEOF(false) {}
 
-  void Open(const char* outFilename, const char* mode);
+  void Open(absl::string_view outFilename, absl::string_view mode);
 
   void Close();