Add Linux build packaging targets to GN

sandbox/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Meta-target that forwards to the proper platform one.
 group("sandbox") {
   if (is_win) {
-    deps = [
+    public_deps = [
       "//sandbox/win:sandbox",
     ]
   } else if (is_mac) {
     # TODO(GYP): Make sandbox compile w/ 10.6 SDK.
     if (false) {
-      deps = [
+      public_deps = [
         "//sandbox/mac:sandbox",
       ]
     }
   } else if (is_linux || is_android) {
-    deps = [
+    public_deps = [
       "//sandbox/linux:sandbox",
     ]
   }
 }