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_to_number.cc

@@ -0,0 +1,90 @@
+/*
+ *  Copyright 2017 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.
+ */
+
+#include "rtc_base/string_to_number.h"
+
+#include <ctype.h>
+
+#include <cerrno>
+#include <cstdlib>
+
+#include "rtc_base/checks.h"
+
+namespace rtc {
+namespace string_to_number_internal {
+
+absl::optional<signed_type> ParseSigned(const char* str, int base) {
+  RTC_DCHECK(str);
+  if (isdigit(str[0]) || str[0] == '-') {
+    char* end = nullptr;
+    errno = 0;
+    const signed_type value = std::strtoll(str, &end, base);
+    if (end && *end == '\0' && errno == 0) {
+      return value;
+    }
+  }
+  return absl::nullopt;
+}
+
+absl::optional<unsigned_type> ParseUnsigned(const char* str, int base) {
+  RTC_DCHECK(str);
+  if (isdigit(str[0]) || str[0] == '-') {
+    // Explicitly discard negative values. std::strtoull parsing causes unsigned
+    // wraparound. We cannot just reject values that start with -, though, since
+    // -0 is perfectly fine, as is -0000000000000000000000000000000.
+    const bool is_negative = str[0] == '-';
+    char* end = nullptr;
+    errno = 0;
+    const unsigned_type value = std::strtoull(str, &end, base);
+    if (end && *end == '\0' && errno == 0 && (value == 0 || !is_negative)) {
+      return value;
+    }
+  }
+  return absl::nullopt;
+}
+
+template <typename T>
+T StrToT(const char* str, char** str_end);
+
+template <>
+inline float StrToT(const char* str, char** str_end) {
+  return std::strtof(str, str_end);
+}
+
+template <>
+inline double StrToT(const char* str, char** str_end) {
+  return std::strtod(str, str_end);
+}
+
+template <>
+inline long double StrToT(const char* str, char** str_end) {
+  return std::strtold(str, str_end);
+}
+
+template <typename T>
+absl::optional<T> ParseFloatingPoint(const char* str) {
+  RTC_DCHECK(str);
+  if (*str == '\0')
+    return absl::nullopt;
+  char* end = nullptr;
+  errno = 0;
+  const T value = StrToT<T>(str, &end);
+  if (end && *end == '\0' && errno == 0) {
+    return value;
+  }
+  return absl::nullopt;
+}
+
+template absl::optional<float> ParseFloatingPoint(const char* str);
+template absl::optional<double> ParseFloatingPoint(const char* str);
+template absl::optional<long double> ParseFloatingPoint(const char* str);
+
+}  // namespace string_to_number_internal
+}  // namespace rtc