Capture/Replay: Allow capturing of external textures With the support for EGL textures enabled we can actually capture the texture content. Bug: angleproject:5822 Change-Id: I386827456d146a54d9790fdd9eadb39b2a6b87e1 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3702350 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Gert Wollny <gert.wollny@collabora.com> Reviewed-by: Cody Northrop <cnorthrop@google.com>