Add root owners to webrtc/OWNERS

For WebRTC inside Chromium, only the webrtc/ directory is present
(as src/third_party/webrtc). That makes it impossible to add DEPS
check_deps rules in Chromium without approval of a webrtc.org owner
(see https://codereview.chromium.org/1818903004).

By having our root owners also be owners in webrtc/, this should be
less confusing.

NOTRY=True

Review-Url: https://codereview.webrtc.org/1934523002
Cr-Commit-Position: refs/heads/master@{#12687}
diff --git a/webrtc/OWNERS b/webrtc/OWNERS
index 057b563..613031f 100644
--- a/webrtc/OWNERS
+++ b/webrtc/OWNERS
@@ -1,3 +1,9 @@
+henrika@webrtc.org
+mflodman@webrtc.org
+niklas.enbom@webrtc.org
+tina.legrand@webrtc.org
+tommi@webrtc.org
+
 per-file *.isolate=kjellander@webrtc.org
 
 # These are for the common case of adding or renaming files. If you're doing