From 873610ca688a6db70280ddeff7d220c047c07e99 Mon Sep 17 00:00:00 2001
From: Mirta Dvornicic <mirtad@webrtc.org>
Date: Thu, 2 Jan 2020 17:10:33 +0100
Subject: [PATCH] Fix updating degradation preference in SetRtpParameters.

Degradation preference could be changed before video send stream
is configured which would cause a crash.

Bug: None
Change-Id: If970e66fba0b9fdb9da789066861d919874de119
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/164463
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Mirta Dvornicic <mirtad@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30141}
---
 media/engine/webrtc_video_engine.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/media/engine/webrtc_video_engine.cc b/media/engine/webrtc_video_engine.cc
index 1e338d5178..c93494b780 100644
--- a/media/engine/webrtc_video_engine.cc
+++ b/media/engine/webrtc_video_engine.cc
@@ -2068,7 +2068,9 @@ webrtc::RTCError WebRtcVideoChannel::WebRtcVideoSendStream::SetRtpParameters(
     UpdateSendState();
   }
   if (new_degradation_preference) {
-    stream_->SetSource(this, GetDegradationPreference());
+    if (source_ && stream_) {
+      stream_->SetSource(this, GetDegradationPreference());
+    }
   }
   return webrtc::RTCError::OK();
 }