Create a MediaCodecVideoTrackRenderer.shouldDropFrame function that can be overriden by a child class. The YouTube override prevents a frame drop if we haven't rendered anything in the last 35 ms.
The YouTube override is off at the moment, I plan to use a server side flag to do a slow and controlled experiment.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=142190774
