Direct3D: add aliasing texture support

In D3D we can alias a resource's allocation and re-use it for
another resource. For example, this is used in the mipmap generator
when we have an sRGB texture. The sRGB formats can't be used in a
UAV, but we can use an aliased texture with the corresponding linear
format, and do the sRGB conversion in the compute shader.

Change-Id: I6995cdecf5be36aafbed5c48e639c09f41ec4f8b
Bug: skia:10446
Reviewed-by: Brian Salomon <>
Commit-Queue: Jim Van Verth <>
5 files changed