Vulkan: Record blit commands inside blit methods. Instead of starting recording blit commands immediately we can record them closer to where we write to the Image directly. This makes it a bit easier to move towards hiding the command buffers. And easier to move to using implicitly generated barriers. Bug: angleproject:2828 Change-Id: Ida7d4081dd41c8ee19c7dc3fb234df1bb065794d Reviewed-on: https://chromium-review.googlesource.com/1254382 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Frank Henigman <fjhenigman@chromium.org>