Remove SkStream_mac.cpp.

This file is a stub. References from supported builds have been removed,
so remove the file.

Change-Id: I21ad98df7157a698fb967fee22d989048f41864f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/294937
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
1 file changed