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/test/mac_capturer.h b/test/mac_capturer.h
new file mode 100644
index 0000000..3d7ee77
--- /dev/null
+++ b/test/mac_capturer.h
@@ -0,0 +1,50 @@
+/*
+ *  Copyright (c) 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.
+ */
+#ifndef TEST_MAC_CAPTURER_H_
+#define TEST_MAC_CAPTURER_H_
+
+#include <memory>
+#include <vector>
+
+#include "api/media_stream_interface.h"
+#include "api/scoped_refptr.h"
+#include "modules/video_capture/video_capture.h"
+#include "rtc_base/thread.h"
+#include "test/test_video_capturer.h"
+
+namespace webrtc {
+namespace test {
+
+class MacCapturer : public TestVideoCapturer,
+                    public rtc::VideoSinkInterface<VideoFrame> {
+ public:
+  static MacCapturer* Create(size_t width,
+                             size_t height,
+                             size_t target_fps,
+                             size_t capture_device_index);
+  ~MacCapturer() override;
+
+  void OnFrame(const VideoFrame& frame) override;
+
+ private:
+  MacCapturer(size_t width,
+              size_t height,
+              size_t target_fps,
+              size_t capture_device_index);
+  void Destroy();
+
+  void* capturer_;
+  void* adapter_;
+};
+
+}  // namespace test
+}  // namespace webrtc
+
+#endif  // TEST_MAC_CAPTURER_H_