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

Source/modules/nfc/NavigatorNfc.h

+// 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.
+
+#ifndef NavigatorNfc_h
+#define NavigatorNfc_h
+
+#include "platform/Supplementable.h"
+#include "platform/heap/Handle.h"
+
+namespace blink {
+
+class Nfc;
+class Navigator;
+class ExecutionContext;
+
+class NavigatorNfc final
+    : public GarbageCollectedFinalized<NavigatorNfc>
+    , public HeapSupplement<Navigator> {
+    USING_GARBAGE_COLLECTED_MIXIN(NavigatorNfc);
+
+public:
+    // Gets, or creates, NavigatorNfc supplement on Navigator.
+    static NavigatorNfc& from(Navigator&);
+
+    static Nfc* nfc(ExecutionContext*, Navigator&);
+
+    DECLARE_TRACE();
+
+private:
+    NavigatorNfc();
+    static const char* supplementName();
+
+    Member<Nfc> m_nfc;
+};
+
+} // namespace blink
+
+#endif // NavigatorNfc_h