SDK / exoplayer

They serve the same purpose. One was defined as single window, multi-period
timeline, while the other was a multi-window, single-period-each timeline.

The combined FakeTimeline uses TimelineWindowDefinitions which allow multi-
window, multi-period fake timelines.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=160808844