build: Remove build system support for gold plugin, except under ChromeOS, take 2.

chrome/test/data/nacl/BUILD.gn

 # 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.
 
+import("//build/config/compiler/compiler.gni")
 import("//build/config/features.gni")
 import("//build/config/nacl/config.gni")
-import("//build/toolchain/toolchain.gni")
 import("//ppapi/native_client/nacl_test_data.gni")
 
 group("nacl") {
   newlib = "//build/toolchain/nacl:clang_newlib_${target_cpu}"
   pnacl = "//build/toolchain/nacl:newlib_pnacl"
   data_deps = [
     ":exit_status_test($newlib)",
     ":exit_status_test($pnacl)",
     ":extension_validation_cache($newlib)",
     ":irt_exception_test($newlib)",
@@ skipping 605 matching lines @@
       "nonsfi/libc_free.nmf",
     ]
     outputs = [
       "${root_build_dir}/nacl_test_data/libc-free/{{source_file_part}}",
     ]
     deps = [
       ":nonsfi_libc_free_nexe",
     ]
   }
 }