Change initial DTLS retransmission timer from 1 second to 50ms.

This will help ensure a timely DTLS handshake when there's packet
loss. It will likely result in spurious retransmissions (since the
RTT is usually > 50ms), but since exponential backoff is still used,
there will at most be ~4 extra retransmissions. For a time-sensitive
application like WebRTC this seems like a reasonable tradeoff.

R=pthatcher@webrtc.org, juberti@chromium.org, juberti@webrtc.org

Review URL: https://codereview.webrtc.org/1981463002 .

Committed: https://crrev.com/1e435628366fb9fed71632369f05928ed857d8ef
Cr-Original-Commit-Position: refs/heads/master@{#12853}
Cr-Commit-Position: refs/heads/master@{#13159}
diff --git a/webrtc/base/logging.cc b/webrtc/base/logging.cc
index 6060362..c951e15 100644
--- a/webrtc/base/logging.cc
+++ b/webrtc/base/logging.cc
@@ -124,7 +124,9 @@
                        const char* module)
     : severity_(sev), tag_(kLibjingle) {
   if (timestamp_) {
-    int64_t time = TimeSince(LogStartTime());
+    // Use SystemTimeMillis so that even if tests use fake clocks, the timestamp
+    // in log messages represents the real system time.
+    int64_t time = TimeDiff(SystemTimeMillis(), LogStartTime());
     // Also ensure WallClockStartTime is initialized, so that it matches
     // LogStartTime.
     WallClockStartTime();
@@ -210,7 +212,7 @@
 }
 
 int64_t LogMessage::LogStartTime() {
-  static const int64_t g_start = TimeMillis();
+  static const int64_t g_start = SystemTimeMillis();
   return g_start;
 }