macOS Sandbox: Add xpc services to the GPU sandbox.

This adds XPC services to the GPU sandbox profile:
  - com.apple.coremedia.videodecoder
  - com.apple.coremedia.videoencoder
  - *apple-extension-service*

Bug: 915934
Change-Id: Ibdbf903497af00af4a0b241e65b49cc646b10937
Reviewed-on: https://chromium-review.googlesource.com/c/1481903Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Greg Kerr <kerrnel@chromium.org>
Auto-Submit: Greg Kerr <kerrnel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634417}

services/service_manager/sandbox/mac/gpu_v2.sb

@@ -42,9 +42,11 @@
 
 ; Needed for VideoToolbox usage - https://crbug.com/767037
 (if (>= os-version 1013)
-  (allow mach-lookup (global-name "com.apple.coremedia.videodecoder"))
-  (allow mach-lookup (global-name "com.apple.coremedia.videoencoder"))
-)
+  (allow mach-lookup
+    (xpc-service-name "com.apple.coremedia.videodecoder")
+    (xpc-service-name "com.apple.coremedia.videoencoder")
+    (xpc-service-name-regex #"\.apple-extension-service$")
+))
 
 (allow sysctl-read
   (sysctl-name "hw.logicalcpu_max")