DCHECK fix for https://codereview.webrtc.org/1769113003/
DCHECK fix for https://codereview.webrtc.org/1769113003/

TBR=stefan@webrtc.org

BUG=webrtc:5514

Review URL: https://codereview.webrtc.org/1770373002 .

Cr-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#11905}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 7b4c9db28a6f9a3b6fead21c9231468a9aa5df52

jchavanton/webrtc,jchavanton/webrtc,jchavanton/webrtc,Alkalyne/webrtctrunk,jchavanton/webrtc,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,jchavanton/webrtc,jchavanton/webrtc,Alkalyne/webrtctrunk,jchavanton/webrtc,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk