Vulkan: functionally complete worker thread Working on enhancing worker thread to completely own primary command buffers. This will include not only processing SCBs from main thread into a primary, but also submitting those command buffers to the queue. The CommandProcessor is a vk::Context so it can handle errors in the worker thread. When the main thread submits tasks to the worker thread it also syncs any outstanding errors from the worker. Include asynchronousCommandProcessing feature that will control whether the worker thread task does it's work in parallel or not. If false, we wait for the thread to complete it's work before letting the main thread continue. If true, the thread can execute in parallel with the main thread. Bug: b/154030730 Bug: b/161912801 Change-Id: I00f8f013d6cbb2af12a172c4f7927855db2f0ebf Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2328992 Commit-Queue: Courtney Goeltzenleuchter <courtneygo@google.com> Reviewed-by: Tim Van Patten <timvp@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org>