media: scaffolding and plumbing for MojoRenderer{Impl, Service}

media/mojo/services/mojo_demuxer_stream_impl.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_MOJO_DEMUXER_STREAM_IMPL_H_
+#define MEDIA_MOJO_SERVICES_MOJO_DEMUXER_STREAM_IMPL_H_
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "media/base/demuxer_stream.h"
+#include "media/mojo/interfaces/demuxer_stream.mojom.h"
+#include "mojo/public/cpp/bindings/interface_impl.h"
+
+namespace media {
+class DemuxerStream;
+
+// This class wraps a media::DemuxerStream and exposes it as a
+// mojo::DemuxerStream for use as a proxy from remote applications.
+class MojoDemuxerStreamImpl : public mojo::InterfaceImpl<mojo::DemuxerStream> {
+ public:
+  // |stream| is the underlying DemuxerStream we are proxying for.
+  // Note: |this| does not take ownership of |stream|.
+  explicit MojoDemuxerStreamImpl(media::DemuxerStream* stream);
+  virtual ~MojoDemuxerStreamImpl();
+
+  // mojo::DemuxerStream implementation.
+  virtual void Read(const mojo::Callback<void(
+     mojo::DemuxerStream::Status,
+     mojo::MediaDecoderBufferPtr)>& callback) OVERRIDE;
+
+  // mojo::InterfaceImpl overrides.
+  virtual void OnConnectionEstablished() OVERRIDE;
+
+ private:
+  // |callback| is the callback that was passed to the initiating Read()
+  //     call by our client.
+  // |status| and |buffer| are the standard media::ReadCB parameters.
+  void OnBufferReady(
+      mojo::Callback<void(mojo::DemuxerStream::Status,
+                          mojo::MediaDecoderBufferPtr)> callback,

[xhwang, 2014/09/10 00:00:52]

nit: typedef this callback?

[tim (not reviewing), 2014/09/10 23:08:29]

OK, although it feels weird to use the typedef in the function signature for the
overridden function above.  Did you want to change that too?

[xhwang, 2014/09/15 04:57:28]

Yeah.. it's a pretty long callback, may just be typedef it in the base class.

[tim (not reviewing), 2014/09/15 21:52:51]

Done.

+      media::DemuxerStream::Status status,

[scherkus (not reviewing), 2014/09/09 20:35:32]

remove media:: here and everywhere else

(80 characters are precious! we shouldn't waste it not needed!)

[tim (not reviewing), 2014/09/10 23:08:29]

Well... there's media::DemuxerStream and mojo::DemuxerStream right now.

I suppose we could convert to using 'module media' in the mojom files and prefix
all the mojom interfaces with 'Mojo' :/  

+      const scoped_refptr<media::DecoderBuffer>& buffer);
+
+  // See constructor.  We do not own |stream_|.
+  media::DemuxerStream* stream_;
+
+  base::WeakPtrFactory<MojoDemuxerStreamImpl> weak_factory_;
+  DISALLOW_COPY_AND_ASSIGN(MojoDemuxerStreamImpl);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_MOJO_SERVICES_MOJO_DEMUXER_STREAM_IMPL_H_