Correct iOS hermetic plist rule.

build/config/mac/base_rules.gni

Index: build/config/mac/base_rules.gni
diff --git a/build/config/mac/base_rules.gni b/build/config/mac/base_rules.gni
index 074074eb347f1eb73e1b31e32a7a6f4711ebd52c..a707bb40668813558120a49766cce05c3c6341f8 100644
--- a/build/config/mac/base_rules.gni
+++ b/build/config/mac/base_rules.gni
@@ -53,6 +53,12 @@ template("convert_plist") {
       rebase_path(invoker.output, root_build_dir),
       rebase_path(invoker.source, root_build_dir),
     ]
+    if (!use_system_xcode) {

[erikchen, 2016/11/28 15:57:10]

Will this be parsed as an unknown argument if it isn't the first argument?

[justincohen, 2016/11/28 19:42:02]

It seems to work here?  I can move it to the front if you want.

+      args += [
+        "--developer_dir",
+        hermetic_xcode_path,
+      ]
+    }
   }
 }