Revert "Remove PlayoutDelayOracle and make RtpSenderVideo guarantee delivery"

This reverts commit 4f68f5398d7fa3d47c449e99893c9bea07bf7ca2.

Reason for revert: Breaks downstream project

Original change's description:
> Remove PlayoutDelayOracle and make RtpSenderVideo guarantee delivery
> 
> The PlayoutDelayOracle was responsible for making sure the PlayoutDelay
> header extension was successfully propagated to the receiving side. Once
> it was determined that the receiver had received a frame with the new
> delay tag, it's no longer necessary to propagate.
> 
> The issue with this implementation is that it is based on max
> extended sequence number reported via RTCP, which makes it often slow
> to react, could theoretically fail to produce desired outcome (max
> received > X does not guarantee X was fully received and decoded), and
> added a lot of code complexity.
> 
> The guarantee of delivery can in fact be accomplished more reliably and
> with less code by making sure to tag each frame until an undiscardable
> frame is sent.
> 
> This allows containing the logic fully within RTPSenderVideo.
> 
> Bug: webrtc:11340
> Change-Id: I2d1d2b6b67f4f07b8b33336f8fcfcde724243eef
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/168221
> Reviewed-by: Stefan Holmer <stefan@webrtc.org>
> Reviewed-by: Sebastian Jansson <srte@webrtc.org>
> Commit-Queue: Erik Språng <sprang@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#30473}

TBR=sprang@webrtc.org,stefan@webrtc.org,srte@webrtc.org

Change-Id: Ide922e680ae36bb69b95e58002482cf5ed57e254
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: webrtc:11340
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/168304
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#30475}

common_types.h

@@ -89,16 +89,8 @@ typedef SpatialLayer SimulcastStream;
 // Note: Given that this gets embedded in a union, it is up-to the owner to
 // initialize these values.
 struct PlayoutDelay {
-  PlayoutDelay(int min_ms, int max_ms) : min_ms(min_ms), max_ms(max_ms) {}
   int min_ms;
   int max_ms;
-
-  static PlayoutDelay Noop() { return PlayoutDelay(-1, -1); }
-
-  bool IsNoop() const { return min_ms == -1 && max_ms == -1; }
-  bool operator==(const PlayoutDelay& rhs) const {
-    return min_ms == rhs.min_ms && max_ms == rhs.max_ms;
-  }
 };
 
 }  // namespace webrtc