GN: Define clang_newlib_arm toolchain for NaCl

ppapi/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.
 
 copy("copy_test_files") {
   visibility = [ ":*" ]
   sources = [
     # Keep "test_case.html.mock-http-headers" with "test_case.html".
     "tests/ppapi_nacl_tests_newlib.nmf",
     "tests/test_case.html",
@@ skipping 179 matching lines @@
       outputs = [
         "${root_build_dir}/{{source_name_part}}_${target_cpu}.nexe",
       ]
       deps = [
         ":ppapi_nacl_tests_newlib",
       ]
     }
   }
 
   group("ppapi_nacl_tests") {
-    deps = []
-    if (target_cpu == "x86" || target_cpu == "x64") {
-      deps += [ ":nacl_tests_copy(//build/toolchain/nacl:clang_newlib_${target_cpu})" ]
-    }
+    deps = [
+      ":nacl_tests_copy(//build/toolchain/nacl:clang_newlib_${target_cpu})",
+    ]
   }
 }