Remove use of PPB_Compositor in TestFlashFullscreenForBrowserUI

PPB_Compositor is going away, so replace with PPB_Graphics3D. Also fix
logic related to submitting frames while callbacks are pending (might be
related to test flakiness).

Bug: 918951
Change-Id: I232c87525f39e268c6fd26072cb465c07fc4256b
Reviewed-on: https://chromium-review.googlesource.com/c/1395144
Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Antoine Labour <piman@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#619980}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: a6ff5bd40da6d03e677ce9ab52d0a740527397b2
2 files changed