Rename PlayoutDelay --> VideoPlayoutDelay, move to api/video/video_timing.h

We can then finally delete the top-level common_types.h, and the
corresponding build target webrtc_common.

Bug: webrtc:7660
Change-Id: I1c1096541477586d90774c7a3405b9d36edec14a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/182800
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Sebastian Jansson <srte@webrtc.org>
Reviewed-by: Erik Språng <sprang@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32044}
diff --git a/api/rtp_headers.h b/api/rtp_headers.h
index 454149c..b9a97c8 100644
--- a/api/rtp_headers.h
+++ b/api/rtp_headers.h
@@ -23,7 +23,6 @@
 #include "api/video/video_content_type.h"
 #include "api/video/video_rotation.h"
 #include "api/video/video_timing.h"
-#include "common_types.h"  // NOLINT (build/include)
 
 namespace webrtc {
 
@@ -142,7 +141,7 @@
   bool has_video_timing;
   VideoSendTiming video_timing;
 
-  PlayoutDelay playout_delay = {-1, -1};
+  VideoPlayoutDelay playout_delay;
 
   // For identification of a stream when ssrc is not signaled. See
   // https://tools.ietf.org/html/draft-ietf-avtext-rid-09