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/PCMFile.cc b/modules/audio_coding/test/PCMFile.cc
index 9ccfa49..e069a42 100644
--- a/modules/audio_coding/test/PCMFile.cc
+++ b/modules/audio_coding/test/PCMFile.cc
@@ -14,6 +14,7 @@
 #include <stdio.h>
 #include <string.h>
 
+#include "absl/strings/string_view.h"
 #include "rtc_base/checks.h"
 #include "test/gtest.h"
 
@@ -103,12 +104,13 @@
   return 0;
 }
 
-void PCMFile::Open(const std::string& file_name,
+void PCMFile::Open(absl::string_view file_name,
                    uint16_t frequency,
-                   const char* mode,
+                   absl::string_view mode,
                    bool auto_rewind) {
-  if ((pcm_file_ = fopen(file_name.c_str(), mode)) == NULL) {
-    printf("Cannot open file %s.\n", file_name.c_str());
+  if ((pcm_file_ = fopen(std::string(file_name).c_str(),
+                         std::string(mode).c_str())) == NULL) {
+    printf("Cannot open file %s.\n", std::string(file_name).c_str());
     ADD_FAILURE() << "Unable to read file";
   }
   frequency_ = frequency;