Allow WindowedFilter to use arbitrary time type instead of QuicTime. No functional change.

net/quic/congestion_control/rtt_stats.cc

Index: net/quic/congestion_control/rtt_stats.cc
diff --git a/net/quic/congestion_control/rtt_stats.cc b/net/quic/congestion_control/rtt_stats.cc
index 9d31caaa3889d7528508c6e2c6990c7a2abd337d..86eb3abb7e70ae01445cefd113c0d0b6d0bbcca0 100644
--- a/net/quic/congestion_control/rtt_stats.cc
+++ b/net/quic/congestion_control/rtt_stats.cc
@@ -37,7 +37,8 @@ RttStats::RttStats()
       num_samples_for_forced_min_(0),
       windowed_min_rtt_(
           QuicTime::Delta::FromMilliseconds(kMinRttWindowLengthMs),
-          QuicTime::Delta::Zero()) {}
+          QuicTime::Delta::Zero(),
+          QuicTime::Zero()) {}
 
 void RttStats::SampleNewWindowedMinRtt(uint32_t num_samples) {
   num_samples_for_forced_min_ = num_samples;