Add sample count to GrVkImageInfo.

Pre-req for allowing rendering to an externally created MSSA VkImage.


Bug: skia:9832

Cq-Include-Trybots: luci.skia.skia.primary:Test-Debian10-Clang-NUC7i5BNK-GPU-IntelIris640-x86_64-Release-All-Vulkan,Test-Win10-Clang-NUC8i5BEK-GPU-IntelIris655-x86_64-Release-All-Vulkan,Test-Win10-Clang-ShuttleA-GPU-RadeonHD7770-x86_64-Release-All-Vulkan,Test-Android-Clang-GalaxyS9-GPU-MaliG72-arm64-Release-All-Android_Vulkan,Test-Android-Clang-GalaxyS7_G930FD-GPU-MaliT880-arm64-Release-All-Android_Vulkan,Test-Android-Clang-GalaxyS20-GPU-MaliG77-arm64-Release-All-Android_Vulkan,Test-Android-Clang-Pixel4XL-GPU-Adreno640-arm64-Release-All-Android_Vulkan,Test-Android-Clang-P30-GPU-MaliG76-arm64-Release-All-Android_Vulkan
Change-Id: Ibf41944c6946dda7e27bdcd509ecd04976fc9ade
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/320262
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
8 files changed