Snap bitmap for SkThreadedBMPDevice::drawBitmapRect

Otherwise, dm --config t8888 -m rects_as_paths will fail in ASAN.

Bug: skia:
Change-Id: I2b69b3544af7303a1e052c67f087d3ac9d26689d
Reviewed-on: https://skia-review.googlesource.com/123685
Auto-Submit: Yuqian Li <liyuqian@google.com>
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Reed <reed@google.com>
2 files changed