media: Introduce DemuxerStreamProvider interface.

media/base/demuxer_stream_provider.h

+// Copyright 2014 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 MEDIA_BASE_DEMUXER_STREAM_PROVIDER_H_
+#define MEDIA_BASE_DEMUXER_STREAM_PROVIDER_H_
+
+#include "media/base/demuxer_stream.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+class MEDIA_EXPORT DemuxerStreamProvider {
+ public:
+  enum Liveness {
+    LIVENESS_UNKNOWN,
+    LIVENESS_RECORDED,
+    LIVENESS_LIVE,
+  };
+
+  DemuxerStreamProvider();
+  virtual ~DemuxerStreamProvider();
+
+  // Returns the first stream of the given stream type (which is not allowed
+  // to be DemuxerStream::TEXT), or NULL if that type of stream is not present.
+  virtual DemuxerStream* GetStream(DemuxerStream::Type type) = 0;
+
+  // Returns liveness of the streams provided, i.e. whether recorded or live.
+  virtual Liveness GetLiveness() const = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DemuxerStreamProvider);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_DEMUXER_STREAM_PROVIDER_H_