Cache video processor output view for video swap chain

crrev.com/1318808 changed SwapChainPresenter to recreate video processor
output view on every PresentToSwapChain in addition to lazy initializing
the video device.  A power regression was noticed on internal AVA bots
around the same time.  This is a speculative fix for the power
regression by reverting to the old behavior of caching the output view.

Bug: 894675
Change-Id: I4130129951d8b9d9efa9aaeee4ba78aa1ef3f778
Reviewed-on: https://chromium-review.googlesource.com/c/1341156
Commit-Queue: Sunny Sachanandani <sunnyps@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609475}
1 file changed