Add support for external video renderers in mojo.

media/mojo/services/demuxer_stream_provider_shim.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_MOJO_SERVICES_DEMUXER_STREAM_PROVIDER_SHIM_H_
+#define MEDIA_MOJO_SERVICES_DEMUXER_STREAM_PROVIDER_SHIM_H_
+
+#include "base/callback.h"
+#include "base/memory/scoped_vector.h"
+#include "base/memory/weak_ptr.h"
+#include "media/base/demuxer_stream_provider.h"
+#include "media/mojo/services/mojo_demuxer_stream_adapter.h"
+
+namespace media {
+
+// DemuxerStreamProvider shim for mojo::DemuxerStreams.
+class DemuxerStreamProviderShim : public DemuxerStreamProvider {
+ public:
+  // Constructs the shim; at least a single audio or video stream must be
+  // provided.  |demuxer_ready_cb| will be called once the streams have been
+  // initialized.  Calling any method before then is an error.
+  DemuxerStreamProviderShim(mojo::DemuxerStreamPtr audio,
+                            mojo::DemuxerStreamPtr video,
+                            const base::Closure& demuxer_ready_cb);
+  ~DemuxerStreamProviderShim() override;
+
+  // DemuxerStreamProvider interface.
+  DemuxerStream* GetStream(DemuxerStream::Type type) override;
+  Liveness GetLiveness() const override;
+
+ private:
+  // Called as each mojo::DemuxerStream becomes ready.  Once all streams are
+  // ready it will fire the |demuxer_ready_cb_| provided during construction.
+  void OnStreamReady();
+
+  // Stored copy the ready callback provided during construction; cleared once
+  // all streams are ready.
+  base::Closure demuxer_ready_cb_;
+
+  // Scoped container for demuxer stream adapters which interface with the
+  // mojo level demuxer streams.  |streams_ready_| tracks how many streams are
+  // ready and is used by OnStreamReady() to know when |demuxer_ready_cb_|
+  // should be fired.
+  ScopedVector<MojoDemuxerStreamAdapter> streams_;
+  size_t streams_ready_;
+
+  // WeakPtrFactorys must always be the last member variable.
+  base::WeakPtrFactory<DemuxerStreamProviderShim> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(DemuxerStreamProviderShim);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_MOJO_SERVICES_DEMUXER_STREAM_PROVIDER_SHIM_H_