exclude src/compute in Google3

Change-Id: I665d21166143d89e575bed0f5b485a69967c1360
Reviewed-on: https://skia-review.googlesource.com/136065
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@google.com>

public.bzl

@@ -270,6 +270,9 @@ BASE_SRCS_ALL = struct(
 
         # Not time for skcms in Google3 yet.
         "src/core/SkColorSpaceXform_skcms.cpp",
+
+        # Compute backend not yet even hooked into Skia.
+	"src/compute/**/*",
     ],
 )