Drop duplicate and out of order VideoFrames in MSTP

Drop videoframes which arrive on a track with duplicate or out of order timestamps, to make
it easier for apps to handle frames without worrying about order.

Bug: 1271175
Change-Id: I20a7312a31d8122c77dccde6d5064b27f0637db3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3304220
Commit-Queue: Tony Herre <toprice@chromium.org>
Reviewed-by: Ben Wagner aka dogben <benjaminwagner@google.com>
Reviewed-by: Johannes Kron <kron@chromium.org>
Cr-Commit-Position: refs/heads/main@{#946371}

mediacapture-insertable-streams/MediaStreamTrackProcessor-video.https.html

@@ -46,10 +46,10 @@ <h1 class="instructions">Description</h1>
   return promise;
 }, "Tests that the reader of a video MediaStreamTrackProcessor produces VideoFrame objects and is closed on track stop while running on a worker");
 
-function makeVideoFrame() {
+function makeVideoFrame(timestamp) {
   const canvas = new OffscreenCanvas(100, 100);
   const ctx = canvas.getContext('2d');
-  return new VideoFrame(canvas);
+  return new VideoFrame(canvas, {timestamp});
 }
 
 promise_test(async t => {
@@ -80,7 +80,7 @@ <h1 class="instructions">Description</h1>
   // Write video frames in different tasks to "slowly" settle the pending read
   // requests.
   for (let i = 0; i<numOperations; i++) {
-     await writer.write(makeVideoFrame());
+     await writer.write(makeVideoFrame(i));
      await new Promise(r=>setTimeout(r,0));
   }