Add ImageHelper to TextureWgpu Bug: angleproject:8547 Change-Id: If718d57704c2548cec27ca15e9adc7bf1a7f92b8 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5381638 Commit-Queue: Liza Burakova <liza@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Matthew Denton <mpdenton@chromium.org>