tree fd1e813a4ec00bcf1bb6b7170220cf600abc3fd7
parent 6c221b40680ff933c7b8f2ac3dfa76b5732aee3e
author mtklein <mtklein@chromium.org> 1448056698 -0800
committer Commit bot <commit-bot@chromium.org> 1448056699 -0800

Fix UB in SkDivBits

This used to:
  DIVBITS_ITER was shifting bits up into the sign bit, which is a no-no.
  This turns numer into a uint32_t to make those defined, and adds a few notes.

  x >= 0 is always true for unsigned x, so we needed a few small logic refactors.

Instead it now:
  Only call SkDivBits if the old behavior is required.
  Usually, just do the divide with /.

BUG=skia:3562

Committed: https://skia.googlesource.com/skia/+/988adddd48322bfa3e3cb0c017cfce71fbbf1123

Committed: https://skia.googlesource.com/skia/+/6c7b104b4c08ae2332a6ce3c8c906da4e8c51e5f

TBR=reed@google.com
No API change.

Review URL: https://codereview.chromium.org/1455163004