... and move it to handleDirtyGraphicsRenderPass.

Bug: angleproject:5528
Change-Id: I416b2fedb1cd924d04fa739aecb65193fd845f6b
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2686441
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>