We want to stop defining OS_POSIX for Fuchsia.
A working CL is available here: https://chromium-review.googlesource.com/c/chromium/src/+/1020375
I am writing a document referencing how I believe we should handle platform switch conditions to unify them once and for all.
The plan to submit the change is similar to how the is_posix change in the build files was handled:
1. Submit as many changes as possible separately from the main CL
2. Switch OS_POSIX to be undefined for Fuchsia
3. Clean up, remove defined(OS_POSIX) && !defined(OS_FUCHSIA) in particular.
Comment 1 by fdegans@chromium.org
, Apr 27 2018