Bump to WebRTC M120 release

Some API deprecation -- ExperimentalAgc and ExperimentalNs are gone.
We're continuing to carry iSAC even though it's gone upstream, but maybe
we'll want to drop that soon.

webrtc/rtc_base/system/file_wrapper.h

@@ -12,11 +12,14 @@
 #define RTC_BASE_SYSTEM_FILE_WRAPPER_H_
 
 #include <stddef.h>
+#include <stdint.h>
 #include <stdio.h>
 #include <stdint.h>
 
 #include <string>
 
+#include "absl/strings/string_view.h"
+
 // Implementation that can read (exclusive) or write from/to a file.
 
 namespace webrtc {
@@ -33,20 +36,16 @@ class FileWrapper final {
  public:
   // Opens a file, in read or write mode. Use the is_open() method on the
   // returned object to check if the open operation was successful. On failure,
-  // and if |error| is non-null, the system errno value is stored at |*error|.
+  // and if `error` is non-null, the system errno value is stored at |*error|.
   // The file is closed by the destructor.
-  static FileWrapper OpenReadOnly(const char* file_name_utf8);
-  static FileWrapper OpenReadOnly(const std::string& file_name_utf8);
-  static FileWrapper OpenWriteOnly(const char* file_name_utf8,
-                                   int* error = nullptr);
-
-  static FileWrapper OpenWriteOnly(const std::string& file_name_utf8,
+  static FileWrapper OpenReadOnly(absl::string_view file_name_utf8);
+  static FileWrapper OpenWriteOnly(absl::string_view file_name_utf8,
                                    int* error = nullptr);
 
   FileWrapper() = default;
 
-  // Takes over ownership of |file|, closing it on destruction. Calling with
-  // null |file| is allowed, and results in a FileWrapper with is_open() false.
+  // Takes over ownership of `file`, closing it on destruction. Calling with
+  // null `file` is allowed, and results in a FileWrapper with is_open() false.
   explicit FileWrapper(FILE* file) : file_(file) {}
   ~FileWrapper() { Close(); }
 
@@ -88,6 +87,11 @@ class FileWrapper final {
   // Seek to given position.
   bool SeekTo(int64_t position);
 
+  // Returns the file size or -1 if a size could not be determined.
+  // (A file size might not exists for non-seekable files or file-like
+  // objects, for example /dev/tty on unix.)
+  long FileSize();
+
   // Returns number of bytes read. Short count indicates EOF or error.
   size_t Read(void* buf, size_t length);