Update to current webrtc library

This is from the upstream library commit id
3326535126e435f1ba647885ce43a8f0f3d317eb, corresponding to Chromium
88.0.4290.1.

webrtc/rtc_base/string_utils.h

@@ -0,0 +1,93 @@
+/*
+ *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#ifndef RTC_BASE_STRING_UTILS_H_
+#define RTC_BASE_STRING_UTILS_H_
+
+#include <ctype.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+
+#if defined(WEBRTC_WIN)
+#include <malloc.h>
+#include <wchar.h>
+#include <windows.h>
+
+#endif  // WEBRTC_WIN
+
+#if defined(WEBRTC_POSIX)
+#include <stdlib.h>
+#include <strings.h>
+#endif  // WEBRTC_POSIX
+
+#include <string>
+
+namespace rtc {
+
+const size_t SIZE_UNKNOWN = static_cast<size_t>(-1);
+
+// Safe version of strncpy that always nul-terminate.
+size_t strcpyn(char* buffer,
+               size_t buflen,
+               const char* source,
+               size_t srclen = SIZE_UNKNOWN);
+
+///////////////////////////////////////////////////////////////////////////////
+// UTF helpers (Windows only)
+///////////////////////////////////////////////////////////////////////////////
+
+#if defined(WEBRTC_WIN)
+
+inline std::wstring ToUtf16(const char* utf8, size_t len) {
+  if (len == 0)
+    return std::wstring();
+  int len16 = ::MultiByteToWideChar(CP_UTF8, 0, utf8, static_cast<int>(len),
+                                    nullptr, 0);
+  std::wstring ws(len16, 0);
+  ::MultiByteToWideChar(CP_UTF8, 0, utf8, static_cast<int>(len), &*ws.begin(),
+                        len16);
+  return ws;
+}
+
+inline std::wstring ToUtf16(const std::string& str) {
+  return ToUtf16(str.data(), str.length());
+}
+
+inline std::string ToUtf8(const wchar_t* wide, size_t len) {
+  if (len == 0)
+    return std::string();
+  int len8 = ::WideCharToMultiByte(CP_UTF8, 0, wide, static_cast<int>(len),
+                                   nullptr, 0, nullptr, nullptr);
+  std::string ns(len8, 0);
+  ::WideCharToMultiByte(CP_UTF8, 0, wide, static_cast<int>(len), &*ns.begin(),
+                        len8, nullptr, nullptr);
+  return ns;
+}
+
+inline std::string ToUtf8(const wchar_t* wide) {
+  return ToUtf8(wide, wcslen(wide));
+}
+
+inline std::string ToUtf8(const std::wstring& wstr) {
+  return ToUtf8(wstr.data(), wstr.length());
+}
+
+#endif  // WEBRTC_WIN
+
+// Remove leading and trailing whitespaces.
+std::string string_trim(const std::string& s);
+
+// TODO(jonasolsson): replace with absl::Hex when that becomes available.
+std::string ToHex(const int i);
+
+}  // namespace rtc
+
+#endif  // RTC_BASE_STRING_UTILS_H_