Remove PaintLayerPaintingInfo::sub_pixel_accumulation

We should use FragmentData::PaintOffset() instead of the offset
calculated from sub_pixel_accumulation and root_layer offset.

Change-Id: Ibf3bd85efaa296240b13d5563e46bcf1de078e53
Bug: 1277748
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3372109


Reviewed-by: Philip Rogers <pdr@chromium.org>
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Cr-Commit-Position: refs/heads/main@{#956765}