Adopt absl::string_view in rtc_base/ (straightforward cases)

Bug: webrtc:13579
Change-Id: I240db6285abb22652242bc0b2ebe9844ec4a45f0
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/258723
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Tomas Gunnarsson <tommi@webrtc.org>
Commit-Queue: Ali Tofigh <alito@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#36561}
diff --git a/modules/audio_processing/audio_processing_unittest.cc b/modules/audio_processing/audio_processing_unittest.cc
index b21a022..e26548a 100644
--- a/modules/audio_processing/audio_processing_unittest.cc
+++ b/modules/audio_processing/audio_processing_unittest.cc
@@ -1600,7 +1600,7 @@
 
   const std::string filename =
       test::TempFilename(test::OutputPath(), "debug_aec");
-  FileWrapper f = FileWrapper::OpenWriteOnly(filename.c_str());
+  FileWrapper f = FileWrapper::OpenWriteOnly(filename);
   ASSERT_TRUE(f.is_open());
 
 #ifdef WEBRTC_AUDIOPROC_DEBUG_DUMP