Add support for direct use of vulkan primary command buffer in render pass.

Change-Id: Icd43965da49963fc9b6ac6c1f7a40be50f2055e8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/239920
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
5 files changed