A framebuffer could contain a mixture of multisampled and
multisampled-render-to-texture attachments. When used as the source of
a glBlitFramebuffer operation, the former requires a resolve while the
latter is a blit. This change fixes this use-case.
Bug: angleproject:4836
Change-Id: I1d39bf25f54df9f8b68304058596a2d1c975f9ba
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2333987
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
