Vulkan: Add ImageHelper::getActualFormat() This is preparation for future CLs. In the future vk::Format may not tell you what actual format is. This CL adds a new method of ImageHelper::getActualFormatID() and ImageHelper::getActualFormat() so that we can use these two APIs and avoid using vk::Format, thus reduce reliance on vk::Format. Bug: b/196456356 Change-Id: Ic50e664e033feb5e066f40269c33cffe96024172 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/3100319 Commit-Queue: Charlie Lao <cclao@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Ian Elliott <ianelliott@google.com>