Reland "Initiate MSAA resolves during DAG generation"

This is a reland of 804f6a0fe7f3c7df5ac69891841ee9cdf6d1121a

Original change's description:
> Initiate MSAA resolves during DAG generation
> 
> Adds an "fIsMSAADirty" flag to GrRenderTargetProxy and switches to
> resolving MSAA in GrTextureResolveRenderTask. This completes our push
> to resolve textures outside of render passes.
> 
> For the time being, we only store a dirty flag on the proxy and still
> rely on the GrRenderTarget itself to track the actual dirty rect. This
> will be followed by a CL that moves the dirty rect out of
> GrRenderTarget and into the proxy.
> 
> Bug: skia:
> Change-Id: I21219a58028bdb4590940210e565133093cd34b3
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/235672
> Commit-Queue: Chris Dalton <csmartdalton@google.com>
> Reviewed-by: Robert Phillips <robertphillips@google.com>

Bug: skia:
Change-Id: I805b3af1404eb7919ae937cff3dfa97921e32c69
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/237482
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
19 files changed