mac: Allow mach lookup of com.apple.GSSCred.

Previously only "org.h5l.kcm" was allowed, but user reports indicate
needing to access the "com.apple.GSSCred" service as well.

R=kerrnel@chromium.org, rsesek@chromium.org

Bug: 1134449
Change-Id: I4c61c82f448de8409c5e5cf3878451a4d69e1264
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2560804Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Cr-Commit-Position: refs/heads/master@{#832131}

AUTHORS

@@ -791,6 +791,7 @@ Pawel Forysiuk <p.forysiuk@samsung.com>
 Paweł Hajdan jr <phajdan.jr@gmail.com>
 Piotr Zarycki <piotr.zarycki@gmail.com>
 Payal Pandey <payal.pandey@samsung.com>
+Pedro Tôrres <t0rr3s.p3dr0@gmail.com>
 Peng Hu <penghu@tencent.com>
 Peng Jiang <leiyi.jp@gmail.com>
 Peng Xinchao <pxinchao@gmail.com>

sandbox/policy/mac/network.sb

@@ -112,6 +112,7 @@
 ; Kerberos support. This should be removed after GSS is moved out of the
 ; network service. https://crbug.com/1017830
 (allow mach-lookup
+  (global-name "com.apple.GSSCred") ; https://crbug.com/1134449
   (global-name "org.h5l.kcm")
 )
 (allow file-read*