[Mac/GN] Add a BUILD.gn file for //chrome/app_shim.

build/config/mac/rules.gni

Index: build/config/mac/rules.gni
diff --git a/build/config/mac/rules.gni b/build/config/mac/rules.gni
index 2105afa790bf46753be9eb3f7fea28e13d9e5630..63577a832e8ffe60ab158676d211ed5d93144d4c 100644
--- a/build/config/mac/rules.gni
+++ b/build/config/mac/rules.gni
@@ -177,17 +177,24 @@ template("mac_app_bundle") {
   _executable_target = target_name + "_executable"
   _executable_bundle_data = _executable_target + "_bundle_data"
 
+  _extra_configs = []
+  if (defined(invoker.extra_configs)) {
+    _extra_configs = invoker.extra_configs
+  }
+
   executable(_executable_target) {
     visibility = [ ":$_executable_bundle_data" ]
     forward_variables_from(invoker,
                            "*",
                            [
                              "assert_no_deps",
+                             "configs",

[brettw, 2016/05/02 21:32:30]

You should still not do this for the same reason I mentioned before. I'm
currently fixing GN to make this a hard error.

[Robert Sesek, 2016/05/02 21:47:49]

Done.

                              "data_deps",
                              "info_plist",
                              "output_name",
                              "visibility",
                            ])
+    configs += _extra_configs

[brettw, 2016/05/02 21:32:30]

Can you replace this whole patch with:
  if (defined(invoker.extra_configs)) {
    configs += invoker.extra_configs
  }
?

[Robert Sesek, 2016/05/02 21:47:49]

Done, without the "invoker." since it's already forwarded from the above.

     output_name = _output_name
     output_dir = "$target_out_dir/$_executable_target"
   }