Refactor MediaResource to be multi-stream capable

chromecast/media/cma/test/frame_segmenter_for_test.cc

Index: chromecast/media/cma/test/frame_segmenter_for_test.cc
diff --git a/chromecast/media/cma/test/frame_segmenter_for_test.cc b/chromecast/media/cma/test/frame_segmenter_for_test.cc
index 5d9406ec01950def579fbb77597fd7403ae85c24..e6442b54bfc3454a5af486ce650f0e347e16871c 100644
--- a/chromecast/media/cma/test/frame_segmenter_for_test.cc
+++ b/chromecast/media/cma/test/frame_segmenter_for_test.cc
@@ -323,8 +323,16 @@ DemuxResult FFmpegDemuxForTest(const base::FilePath& filepath,
                      false);
   init_event.RunAndWaitForStatus(::media::PIPELINE_OK);
 
-  ::media::DemuxerStream* stream = demuxer.GetStream(
-      audio ? ::media::DemuxerStream::AUDIO : ::media::DemuxerStream::VIDEO);
+  std::vector<::media::DemuxerStream*> streams = demuxer.GetStreams();
+  ::media::DemuxerStream* stream = nullptr;
+  ::media::DemuxerStream::Type target_type =
+      audio ? ::media::DemuxerStream::AUDIO : ::media::DemuxerStream::VIDEO;
+  for (const auto& demuxer_stream : streams) {
+    if (demuxer_stream->type() == target_type) {
+      stream = demuxer_stream;
+      break;
+    }
+  }
   CHECK(stream);
 
   DemuxResult demux_result;