Finish plumbing MojoVideoDecoder.

media/mojo/interfaces/video_decoder.mojom

+// Copyright 2016 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.
+
+module media.interfaces;
+
+import "media/mojo/interfaces/media_types.mojom";
+
+interface VideoDecoder {

[xhwang, 2016/05/05 17:26:37]

Please add comments for these new interfaces.

[sandersd (OOO until July 31), 2016/05/06 01:23:55]

Done.

+  Initialize(VideoDecoderClient client,
+             handle<data_pipe_consumer> decoder_buffer_pipe);
+  Configure(VideoDecoderConfig config, bool low_delay) => (bool success);

[xhwang, 2016/05/05 17:26:37]

What's the plan around this? For now (to commit it), shall we just merge these
two calls into one Initialize()?

In AudioDecoder, the Initialize() call takes both AudioDecoderClient and
AudioDecoderConfig: 
https://code.google.com/p/chromium/codesearch#chromium/src/media/mojo/interfa...

[sandersd (OOO until July 31), 2016/05/06 01:23:55]

I don't think it makes sense to merge them, and I don't see anything wrong with
having two methods.

What advantage do you see?

[xhwang, 2016/05/06 17:44:44]

I don't remember why we had them separate (there was a reason) but from the
current code it just doesn't seem necessary. Feel free to keep as is and we can
revisit later.

That being said, can we switch the names Initialize() and Configure() given
Configure() always calls media::VideoDecoder::Initialize()?

[sandersd (OOO until July 31), 2016/05/06 18:01:54]

I would rather start a discussion about renaming
media::VideoDecoder::Initialize() to media::VideoDecoder::Configure(). The
current name is rather confusing.

+  Decode(DecoderBuffer buffer) => (DecodeStatus status);
+  Reset() => ();
+};
+
+interface VideoDecoderClient {
+  OnVideoFrameDecoded(VideoFrame frame);
+};