Fix coverage build.
Fix coverage build.

NOTICE: The coverage build is not officially supported and may break
at any point.
Patch receieved from johan.ahlers@gmail.com.

BUG=webrtc:5754
NOTRY=True
TBR=henrika@webrtc.org

Review URL: https://codereview.webrtc.org/1875193002

Cr-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#12420}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 6e6941f4090a080d6d6b234d9301e424946b6314

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