[webnfc]: Step 1: Add NavigatorNfc, Nfc and Layout tests.

Source/modules/nfc/Nfc.idl

Index: Source/modules/nfc/Nfc.idl
diff --git a/Source/modules/nfc/Nfc.idl b/Source/modules/nfc/Nfc.idl
new file mode 100644
index 0000000000000000000000000000000000000000..4a35922892eaf1244acdecaed4285cd424ebc12a
--- /dev/null
+++ b/Source/modules/nfc/Nfc.idl
@@ -0,0 +1,13 @@
+// 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.
+
+// https://w3c.github.io/web-nfc/#idl-def-NFC
+
+[
+  GarbageCollected,
+  ActiveDOMObject,
+  RuntimeEnabled=Nfc,
+] interface Nfc {
+   [CallWith=ScriptState] Promise<NfcAdapter> requestAdapter ();
+};