D3D9: Implement the CPU-copy path for CopyTextureCHROMIUM. This path is hit for LUMA formats. Only copy from storage to image when the storage is renderable, otherwise it already has up-to-date data. D3D9 cannot sync storage to image without it being renderable. Commit the region after CPU copies to make sure everything is synchronized afterwards. TEST=conformance/textures/canvas/tex-2d-luminance_alpha-luminance_alpha-unsigned_byte.html BUG=angleproject:2192 Change-Id: I74ff748bd051a52cf472ca7ff77f54dfb5ba65b9 Reviewed-on: https://chromium-review.googlesource.com/730493 Commit-Queue: Geoff Lang <geofflang@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>