Fix issue where the first audio packets significantly impacts initial BWE negatively.

webrtc/video/rampup_tests.h

Index: webrtc/video/rampup_tests.h
diff --git a/webrtc/video/rampup_tests.h b/webrtc/video/rampup_tests.h
index 2d9187d99e016abea0941c06fcdcac05a91587b7..ae9e9d95dba6135c6c6f4b666ddbc1fd84314563 100644
--- a/webrtc/video/rampup_tests.h
+++ b/webrtc/video/rampup_tests.h
@@ -128,6 +128,7 @@ class LowRateStreamObserver : public test::DirectTransport,
   const bool rtx_used_;
   const rtc::scoped_ptr<EventWrapper> test_done_;
   const rtc::scoped_ptr<RtpHeaderParser> rtp_parser_;
+  const rtc::scoped_ptr<RTPPayloadRegistry> payload_registry_;
   rtc::scoped_ptr<RtpRtcp> rtp_rtcp_;
   internal::TransportAdapter feedback_transport_;
   const rtc::scoped_ptr<ReceiveStatistics> receive_stats_;