Use CallStats for RTT in Call, rather than VideoSendStream::GetRtt()

webrtc/video/call_stats_unittest.cc

Index: webrtc/video/call_stats_unittest.cc
diff --git a/webrtc/video/call_stats_unittest.cc b/webrtc/video/call_stats_unittest.cc
index 6226a5bf6e751cbc798de4b80fb2f207b665075e..5c57a1731bc8e4453d0257dfe380fb793ce446b4 100644
--- a/webrtc/video/call_stats_unittest.cc
+++ b/webrtc/video/call_stats_unittest.cc
@@ -45,7 +45,7 @@ TEST_F(CallStatsTest, AddAndTriggerCallback) {
   RtcpRttStats* rtcp_rtt_stats = call_stats_->rtcp_rtt_stats();
   call_stats_->RegisterStatsObserver(&stats_observer);
   fake_clock_.AdvanceTimeMilliseconds(1000);
-  EXPECT_EQ(0, rtcp_rtt_stats->LastProcessedRtt());
+  EXPECT_EQ(-1, rtcp_rtt_stats->LastProcessedRtt());
 
   const int64_t kRtt = 25;
   rtcp_rtt_stats->OnRttUpdate(kRtt);
@@ -57,7 +57,7 @@ TEST_F(CallStatsTest, AddAndTriggerCallback) {
   fake_clock_.AdvanceTimeMilliseconds(kRttTimeOutMs);
   EXPECT_CALL(stats_observer, OnRttUpdate(_, _)).Times(0);
   call_stats_->Process();
-  EXPECT_EQ(0, rtcp_rtt_stats->LastProcessedRtt());
+  EXPECT_EQ(-1, rtcp_rtt_stats->LastProcessedRtt());
 
   call_stats_->DeregisterStatsObserver(&stats_observer);
 }