mediaplayer: limit scheduling video frames into the future

This addresses when video timestamps jumps before an audio timestamp,
but still works on slideshow video clips (<=1fps).

This, however, will not skip time-changes on video-only live video
streams, as we cannot distinguish live slideshow video clips from
non-slideshow ones.

Bug: 18032127
Change-Id: I959a714edfe1c8cf3b84704c693dcd1b3e5b7855