1 files changed, 46 insertions, 0 deletions
diff --git a/chromium/third_party/blink/renderer/modules/mediarecorder/track_recorder.h b/chromium/third_party/blink/renderer/modules/mediarecorder/track_recorder.h
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index 00000000000..bd13d24f5ba
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+++ b/chromium/third_party/blink/renderer/modules/mediarecorder/track_recorder.h
@@ -0,0 +1,46 @@
+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef THIRD_PARTY_BLINK_RENDERER_MODULES_MEDIARECORDER_TRACK_RECORDER_H_
+#define THIRD_PARTY_BLINK_RENDERER_MODULES_MEDIARECORDER_TRACK_RECORDER_H_
+
+#include "third_party/blink/public/platform/modules/mediastream/web_media_stream_sink.h"
+#include "third_party/blink/renderer/modules/modules_export.h"
+#include "third_party/blink/renderer/platform/heap/garbage_collected.h"
+
+namespace blink {
+
+// This class exists to give MediaRecorder support for behavior related to
+// all tracks ending.
+// It's a template because VideoTrackRecorder and AudioTrackRecorder inherit
+// from different base classes.
+// Note: this class supports instantiation with classes that inherit from
+// WebMediaStreamSink.
+template <class MediaStreamSink>
+class TrackRecorder : public MediaStreamSink {
+ public:
+  explicit TrackRecorder(base::OnceClosure track_ended_cb);
+  ~TrackRecorder() override = default;
+
+  // WebMediaStreamSink
+  void OnReadyStateChanged(WebMediaStreamSource::ReadyState state) override;
+
+ private:
+  base::OnceClosure track_ended_cb_;
+};
+
+template <class MediaStreamSink>
+TrackRecorder<MediaStreamSink>::TrackRecorder(base::OnceClosure track_ended_cb)
+    : track_ended_cb_(std::move(track_ended_cb)) {}
+
+template <class MediaStreamSink>
+void TrackRecorder<MediaStreamSink>::OnReadyStateChanged(
+    WebMediaStreamSource::ReadyState state) {
+  if (state == WebMediaStreamSource::kReadyStateEnded)
+    std::move(track_ended_cb_).Run();
+}
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_MODULES_MEDIARECORDER_TRACK_RECORDER_H_