[Device Service] Decouple NFC implementation from //content

device/nfc/nfc_provider.mojom

Index: device/nfc/nfc_provider.mojom
diff --git a/device/nfc/nfc_provider.mojom b/device/nfc/nfc_provider.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..030ad6fe450a2e72c62ad67247397cd73e630ba9
--- /dev/null
+++ b/device/nfc/nfc_provider.mojom
@@ -0,0 +1,15 @@
+// Copyright 2017 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.
+
+// TODO(blundell): This should be moved to device.mojom.
+module device.nfc.mojom;
+
+import "device/nfc/nfc.mojom";
+
+interface NFCProvider {
+  // Gets an NFC that is associated with |host_id|. |host_id|
+  // is used to obtain the Activity that this NFC instance should use on
+  // Android (see NFCDelegate.java).
+  GetNFCForHost(int32 host_id, NFC& nfc);
+};