Remove framemarking RTP extension.

BUG=webrtc:11637

Change-Id: I47f8e22473429c9762956444e27cfbafb201b208
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/176442
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31522}
diff --git a/api/rtp_headers.cc b/api/rtp_headers.cc
index bf973b6..e0ad9eb 100644
--- a/api/rtp_headers.cc
+++ b/api/rtp_headers.cc
@@ -26,9 +26,7 @@
       videoRotation(kVideoRotation_0),
       hasVideoContentType(false),
       videoContentType(VideoContentType::UNSPECIFIED),
-      has_video_timing(false),
-      has_frame_marking(false),
-      frame_marking({false, false, false, false, false, 0xFF, 0, 0}) {}
+      has_video_timing(false) {}
 
 RTPHeaderExtension::RTPHeaderExtension(const RTPHeaderExtension& other) =
     default;