Re-land: Remove FX_Alloc() null checks now that it can't return NULL.

Fixes the ordering of some assignments broken when converting to checked
numerics in CFX_PathData::AddPointCount().

Original Review URL: https://codereview.chromium.org/1142713005

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1135893008
48 files changed