GitLab

Report the delta between the swap-time in the renderer, and the
presentation time in the gpu. This would allow us to understand
how switching to presentation-time would affect the paint-timing
metrics.

BUG=899847

Change-Id: I31dd6f5f9ef159e464d7616d2ad04a9c971d7d4a
Reviewed-on: https://chromium-review.googlesource.com/c/1305249Reviewed-by: Bryan McQuade <bmcquade@chromium.org>
Reviewed-by: Mark Pearson <mpearson@chromium.org>
Reviewed-by: Antoine Labour <piman@chromium.org>
Reviewed-by: Timothy Dresser <tdresser@chromium.org>
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#606288}