Use CrossThreadBindOnce in MockMediaStreamVideoSource

... when posting tasks. A task posted runs once, so
CrossThreadBindRepeating is not strictly correct.

This is now possible, after [1].

[1] crrev.com/c/1750043

R=jbroman@chromium.org

Change-Id: I3d783e09b91aa4b0fa4274d83600d401873fb45f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1752075
Commit-Queue: Antonio Gomes <tonikitoo@igalia.com>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#686554}

third_party/blink/renderer/modules/mediastream/mock_media_stream_video_source.cc

@@ -55,10 +55,9 @@ void MockMediaStreamVideoSource::RequestRefreshFrame() {
     const scoped_refptr<media::VideoFrame> frame =
         media::VideoFrame::CreateColorFrame(format_.frame_size, 0, 0, 0,
                                             base::TimeDelta());
-    // TODO(crbug.com/964947): Remove the rebind of |frame_callback_|.
     PostCrossThreadTask(
         *io_task_runner(), FROM_HERE,
-        CrossThreadBindRepeating(frame_callback_, frame, base::TimeTicks()));
+        CrossThreadBindOnce(frame_callback_, frame, base::TimeTicks()));
   }
 }
 
@@ -97,11 +96,9 @@ void MockMediaStreamVideoSource::DeliverVideoFrame(
     scoped_refptr<media::VideoFrame> frame) {
   DCHECK(!is_stopped_for_restart_);
   DCHECK(!frame_callback_.is_null());
-  // TODO(crbug.com/964947): Remove the rebind of |frame_callback_|.
-  PostCrossThreadTask(
-      *io_task_runner(), FROM_HERE,
-      CrossThreadBindRepeating(frame_callback_, std::move(frame),
-                               base::TimeTicks()));
+  PostCrossThreadTask(*io_task_runner(), FROM_HERE,
+                      CrossThreadBindOnce(frame_callback_, std::move(frame),
+                                          base::TimeTicks()));
 }
 
 void MockMediaStreamVideoSource::StopSourceForRestartImpl() {