GN: Enable PNaCl plugin compilation for the key_tester app.

remoting/tools/javascript_key_tester/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/features.gni")
+
+if (enable_pnacl) {
+  group("javascript_key_tester") {
+    deps = [
+      ":javascript_key_tester_copies",
+    ]
+  }
+
+  copy("javascript_key_tester_copies") {
+    pexe_dir = get_label_info(
+            "pnacl:remoting_key_tester_newlib(//native_client/build/toolchain/nacl:newlib_pnacl)",
+            "root_out_dir")
+
+    sources = [
+      "$pexe_dir/remoting_key_tester_newlib.pexe",
+      "background.js",
+      "chord_tracker.js",
+      "event_listeners.js",
+      "icon_128.png",
+      "main.css",
+      "main.html",
+      "main.js",
+      "manifest.json",
+      "pnacl/remoting_key_tester.nmf",
+    ]
+
+    outputs = [
+      "$target_out_dir/remoting/key_tester/{{source_file_part}}",
+    ]
+
+    deps = [
+      ":javascript_key_tester_jscompile",
+      "pnacl:remoting_key_tester_newlib(//native_client/build/toolchain/nacl:newlib_pnacl)",
+    ]
+  }
+
+  group("javascript_key_tester_jscompile") {
+    # TODO(GYP): crbug.com/471926 add support for run_jscompile=true.
+    run_jscompile = false
+    if (run_jscompile) {
+    }
+  }
+}