nfc: Add native NFC API definitions.

device/nfc/nfc_adapter_factory.h

+// Copyright (c) 2013 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 DEVICE_NFC_NFC_ADAPTER_FACTORY_H_
+#define DEVICE_NFC_NFC_ADAPTER_FACTORY_H_
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "device/nfc/nfc_adapter.h"
+
+namespace device {
+
+// NfcAdapterFactory is a class that contains static methods, which
+// instantiate either a specific NFC adapter, or the generic "default
+// adapter" which may change depending on availability.
+class NfcAdapterFactory {
+ public:
+  typedef base::Callback<void(scoped_refptr<NfcAdapter>)> AdapterCallback;
+
+  // Returns true if NFC is available for the current platform.
+  static bool IsNfcAvailable();
+
+  // Returns the shared instance of the default adapter, creating and
+  // initializing it if necessary. |callback| is called with the adapter
+  // instance passed only once the adapter is fully initialized and ready to
+  // use.
+  static void GetAdapter(const AdapterCallback& callback);
+};
+
+}  // namespace device
+
+#endif  // DEVICE_NFC_NFC_ADAPTER_FACTORY_H_