Adds a new helper that creates a GrBackendRenderTarget using
GrGpu and then wraps it in a SkSurface. Uses the SkSurface
release proc to delete the BERT using GrGpu.
Upgrades GrGpu::createTestingOnlyBackendRenderTarget to create MSAA
buffers.
Updates many tests/tool to call sites to use the helper instead of
SkSurface::MakeFromBackendTextureAsRenderTarget.
Adds syncToCpu bool to SkSurface:: and GrContext::flushAndSubmit.
Bug: skia:9832
Change-Id: I73a8f0ce09dc6523729af0814464c6b6657fda06
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/293683
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>