GitLab

Adjust the events to be more accurate. "WaitForSwap" starts when display
compositor thread starts issuing the swap buffers command. "Swap" starts
when the GPU thread starts running the swap buffers task.
"WaitForPresentation" starts when the swap buffers command has been
issued and ends at presentation time.

Bug: none
Change-Id: Ia1aa9f64f946c24b03b8c720b72ca35673f86e56
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1876973Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Sadrul Chowdhury <sadrul@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709914}