Revert of Reduce dependencies on rtc::FileSystem in FileRotatingStream tests...

webrtc/test/testsupport/fileutils.cc

Index: webrtc/test/testsupport/fileutils.cc
diff --git a/webrtc/test/testsupport/fileutils.cc b/webrtc/test/testsupport/fileutils.cc
index 02ef06580bbcec4203d46ac1c23f42d4e279ebd6..899bf31f9070ac5c5a9166655ca3a164c461e110 100644
--- a/webrtc/test/testsupport/fileutils.cc
+++ b/webrtc/test/testsupport/fileutils.cc
@@ -232,22 +232,6 @@
   return true;
 }
 
-bool RemoveDir(const std::string& directory_name) {
-#ifdef WIN32
-    return RemoveDirectoryA(directory_name.c_str()) != FALSE;
-#else
-    return rmdir(directory_name.c_str()) == 0;
-#endif
-}
-
-bool RemoveFile(const std::string& file_name) {
-#ifdef WIN32
-  return DeleteFileA(file_name.c_str()) != FALSE;
-#else
-  return unlink(file_name.c_str()) == 0;
-#endif
-}
-
 std::string ResourcePath(const std::string& name,
                          const std::string& extension) {
 #if defined(WEBRTC_IOS)