This is a small refactor in preparation for exposing GetCurrentTexture
on the SwapChain.
Bug: dawn:1551
Change-Id: I7cc8ec4a9042f48c4af7b2cc2126b1d9248a2003
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/133462
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Loko Kung <lokokung@google.com>