The TrackSelector API will look like:
TrackSelection[] selectTrack(
TrackRenderer[] renderers, TrackGroup[] trackGroups);
In this CL:
- SampleSources return TrackGroup[], so that the result can be easily
passed to the selector.
- TrackStream gets its own file to sit alongside other Track* classes.
- A TrackSelection object is introduced to encapsulate group and track
indices.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=115251331
