Use CrossThreadBindOnce in MediaStreamVideoCapturerSourceTest

... 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

BUG=964922
R=jbroman@chromium.org

Change-Id: Ic1937f017ec6cd5a532b99a1f270f2ce2a99b8dd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1752078
Commit-Queue: Antonio Gomes <tonikitoo@igalia.com>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#686674}

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

@@ -54,7 +54,7 @@ class MockVideoCapturerSource : public media::VideoCapturerSource {
   void SetRunning(bool is_running) {
     PostCrossThreadTask(*scheduler::GetSingleThreadTaskRunnerForTesting(),
                         FROM_HERE,
-                        CrossThreadBindRepeating(running_cb_, is_running));
+                        CrossThreadBindOnce(running_cb_, is_running));
   }
   const media::VideoCaptureParams& capture_params() const {
     return capture_params_;
@@ -246,9 +246,9 @@ TEST_F(MediaStreamVideoCapturerSourceTest, CaptureTimeAndMetadataPlumbing) {
   const scoped_refptr<media::VideoFrame> frame =
       media::VideoFrame::CreateBlackFrame(gfx::Size(2, 2));
   frame->metadata()->SetDouble(media::VideoFrameMetadata::FRAME_RATE, 30.0);
-  PostCrossThreadTask(*Platform::Current()->GetIOTaskRunner(), FROM_HERE,
-                      CrossThreadBindRepeating(deliver_frame_cb, frame,
-                                               reference_capture_time));
+  PostCrossThreadTask(
+      *Platform::Current()->GetIOTaskRunner(), FROM_HERE,
+      CrossThreadBindOnce(deliver_frame_cb, frame, reference_capture_time));
   run_loop.Run();
   fake_sink.DisconnectFromTrack();
   EXPECT_EQ(reference_capture_time, capture_time);