RtpPacketHistory rewritten to use RtpPacket class.

webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc

Index: webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc
diff --git a/webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc b/webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc
index d04ff4d200aa80c75fae2ca65509886e162f27b5..c6a9723c4c55e59568a4ca3995f0393b396e06e9 100644
--- a/webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc
+++ b/webrtc/modules/rtp_rtcp/source/rtp_sender_unittest.cc
@@ -147,6 +147,7 @@ class RtpSenderTest : public ::testing::Test {
         &seq_num_allocator_, nullptr, nullptr, nullptr, nullptr,
         &mock_rtc_event_log_, &send_packet_observer_));
     rtp_sender_->SetSequenceNumber(kSeqNum);
+    rtp_sender_->SetSendPayloadType(kPayload);
   }
 
   SimulatedClock fake_clock_;