GN: forward_variables_from shouldn't clobber vars.

testing/test.gni

 # Copyright 2015 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.
 
 # ==============================================================================
 # TEST SETUP
 # ==============================================================================
 
 template("_gen_isolate") {
   testonly = true
@@ skipping 79 matching lines @@
     if (_generate_device_isolate) {
       _allow_odd_runtime_deps = defined(invoker.allow_odd_runtime_deps) &&
                                 invoker.allow_odd_runtime_deps
 
       # The device isolate is needed at runtime, so it cannot go in
       # target_gen_dir, as builder/tester configurations do not include it.
       _target_dir_name = get_label_info(":$target_name", "dir")
       _device_isolate_path = "$root_out_dir/gen.runtime/$_target_dir_name/$target_name.device.isolate"
       _gen_isolate_target_name = "${target_name}__isolate"
       _gen_isolate(_gen_isolate_target_name) {
-        data_deps = []
         forward_variables_from(invoker,
                                [
                                  "data",
                                  "data_deps",
                                  "deps",
                                  "public_deps",
                                ])
         assert_no_odd_data = !_allow_odd_runtime_deps
         output = _device_isolate_path
         apply_device_filters = true
@@ skipping 231 matching lines @@
     if (defined(invoker.output_name) && target_name != invoker.output_name) {
       group("${invoker.output_name}_run") {
         testonly = true
         deps = [
           ":${invoker.target_name}",
         ]
       }
     }
   }
 }