Googler 7d6f02dc50 Only set hadKeyframe flag to true if we end up muxing the frame.
If we throw away the first keyframe (because it does not contain any bytes to read), we shouldn't behave as if we had written a keyframe to our track. We should instead continue waiting for the first (valid) keyframe.

PiperOrigin-RevId: 554579146
2023-08-10 12:00:51 +00:00
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