Proposal: Checked Malloc Size for Skia

[Kalvin Lee]

Hi folks,

We'd like to propose some changes to improve memory safety in Skia. (Google-internal folks may recall Stephen's "Protecting `malloc()` from integer overflows" proposal --- this is a subset of that.)

Please see the proposal here. (All Chromium committers should have comment access --- but feel free to ping if that doesn't include you.)

All comments and feedback welcome! Thank you in advance.

Kalvin