Make mojo renderer capable of supporting multiple streams/tracks

media/mojo/services/demuxer_stream_provider_shim.cc

 // 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.
 
 #include "media/mojo/services/demuxer_stream_provider_shim.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback_helpers.h"
 
 namespace media {
 
 DemuxerStreamProviderShim::DemuxerStreamProviderShim(
-    mojom::DemuxerStreamPtr audio,
-    mojom::DemuxerStreamPtr video,
+    std::vector<mojom::DemuxerStreamPtr> streams,
     const base::Closure& demuxer_ready_cb)
     : demuxer_ready_cb_(demuxer_ready_cb),
       streams_ready_(0),
       weak_factory_(this) {
-  DCHECK(audio || video);
+  DCHECK(!streams.empty());
   DCHECK(!demuxer_ready_cb_.is_null());
 
-  if (audio) {
-    streams_.push_back(new MojoDemuxerStreamAdapter(
-        std::move(audio), base::Bind(&DemuxerStreamProviderShim::OnStreamReady,
-                                     weak_factory_.GetWeakPtr())));
-  }
-
-  if (video) {
-    streams_.push_back(new MojoDemuxerStreamAdapter(
-        std::move(video), base::Bind(&DemuxerStreamProviderShim::OnStreamReady,
-                                     weak_factory_.GetWeakPtr())));
+  for (auto& s : streams) {
+    streams_.emplace_back(new MojoDemuxerStreamAdapter(
+        std::move(s), base::Bind(&DemuxerStreamProviderShim::OnStreamReady,
+                                 weak_factory_.GetWeakPtr())));
   }
 }
 
 DemuxerStreamProviderShim::~DemuxerStreamProviderShim() {
 }
 
 DemuxerStream* DemuxerStreamProviderShim::GetStream(DemuxerStream::Type type) {
   DCHECK(demuxer_ready_cb_.is_null());
-  for (auto* stream : streams_) {
+  for (auto& stream : streams_) {
     if (stream->type() == type)
-      return stream;
+      return stream.get();

[xhwang, 2017/01/31 00:15:21]

Add a comment that we only return the first stream, and a TODO to support
multiple streams.

[servolk, 2017/01/31 01:10:40]

Done. Although https://codereview.chromium.org/2491043003/ already has changes
which make this comment/TODO immediately obsolete :)

   }
 
   return nullptr;
 }
 
 void DemuxerStreamProviderShim::OnStreamReady() {
   if (++streams_ready_ == streams_.size())
     base::ResetAndReturn(&demuxer_ready_cb_).Run();
 }
 
 }  // namespace media