Abort on OOM by default in FX_Alloc().

Add a FX_TryAlloc() for those few cases where we might need to continue
in face of OOM.

Remove FX_AllocNL() (the context of its use would suggest that NL
means "No Limit"). This is used for some big allocations, so replace
it with TryAlloc().  Large allocations may be worth trying to continue
from, since there are few and they have a large chance of failing.

R=thestig@chromium.org

Review URL: https://codereview.chromium.org/1128043009
10 files changed