*** Reason for rollback ***
causes b/76391022, motion still playback in Photos is broken
*** Original change description ***
Used fixed time frame in clipping media period.
Currently, whenever the clipping is updated, we move the time frame of the
clipped period to start at 0. This causes problems when we are already playing
this period and the renderer position does no longer match the stream
positions.
This change keeps the time frame of the clipped media period as it is and
instead specifies the offset of the window in the period.
***
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=190628272
82b72c9358