Rewrite video_loopback to use new mac capturer.

The old one has been deprecated for a long time.

Bug: webrtc:6333, webrtc:6898, webrtc:7861
Change-Id: Ib9b798262817e80019afcacc5b41d18957a28101
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/124827
Reviewed-by: Stefan Holmer <stefan@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Peter Hanspers <peterhanspers@webrtc.org>
Commit-Queue: Kári Helgason <kthelgason@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26993}
diff --git a/video/video_loopback_main.cc b/video/video_loopback_main.cc
new file mode 100644
index 0000000..f4e5cdd
--- /dev/null
+++ b/video/video_loopback_main.cc
@@ -0,0 +1,15 @@
+/*
+ *  Copyright 2019 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "video/video_loopback.h"
+
+int main(int argc, char* argv[]) {
+  webrtc::RunLoopbackTest(argc, argv);
+}