Provide method for returning certificate expiration timestamp.

webrtc/base/timeutils.h

 /*
  *  Copyright 2005 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 WEBRTC_BASE_TIMEUTILS_H_
 #define WEBRTC_BASE_TIMEUTILS_H_
 
+#include <ctime>
 #include <time.h>
 
 #include "webrtc/base/basictypes.h"
 
 namespace rtc {
 
 static const int64_t kNumMillisecsPerSec = INT64_C(1000);
 static const int64_t kNumMicrosecsPerSec = INT64_C(1000000);
 static const int64_t kNumNanosecsPerSec = INT64_C(1000000000);
 
@@ skipping 62 matching lines @@
  public:
   TimestampWrapAroundHandler();
 
   int64_t Unwrap(uint32_t ts);
 
  private:
   uint32_t last_ts_;
   int64_t num_wrap_;
 };
 
+// Convert from std::tm, which is relative to 1900-01-01 00:00 to number of
+// seconds from 1970-01-01 00:00 ("epoch").  Don't return time_t since that
+// is still 32 bits on many systems.
+int64_t TmToSeconds(const std::tm& tm);
+
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_TIMEUTILS_H_