Host fingerprint mojo service within the device service.

services/device/public/interfaces/fingerprint.mojom

Index: services/device/public/interfaces/fingerprint.mojom
diff --git a/services/device/public/interfaces/fingerprint.mojom b/services/device/public/interfaces/fingerprint.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..87e3dbad806a74dda3b27ec9463d1c128c228c64
--- /dev/null
+++ b/services/device/public/interfaces/fingerprint.mojom
@@ -0,0 +1,60 @@
+// 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.
+
+module device.mojom;

[blundell, 2017/02/22 15:20:06]

Could you add an OWNERS file in this directory and have per-file ownership of
fingerprint.mojom that points to //services/device/fingerprint (see
//components/OWNERS for examples of what I mean)?

[xiaoyinh(OOO Sep 11-29), 2017/02/22 21:03:17]

This directory already have a OWNER file that link all the mojom files to
SECURITY_OWNERS
per-file *.mojom=file://ipc/SECURITY_OWNERS
Is that possible to link a secondary owner to the same file?

+
+// Interface for obeserving biod signals.

[blundell, 2017/02/22 15:20:09]

hmm, is biod ChromeOS-specific? Seems a little strange to have as a concept in
the interface if so.

[xiaoyinh(OOO Sep 11-29), 2017/02/22 21:03:17]

Yes, biod is chromeos-specific, and fingerprint interface is also
chromeos-specific. The purpose of defining a mojom interface is to make easier
communication(less layers) with webui and arc++.
Please let me know if/how I can make things more clear.

+interface BiodObserver{
+  // Called when biometics device powers up or is restarted.
+  OnRestarted();
+
+  // Called whenever a user attempts a scan. |scan_result| tells whether the
+  // scan was succesful. |is_complete| tells whether enrollment is complete
+  // and now over.
+  OnScanned(uint32 scan_result, bool is_complete);
+
+  // Called to indicate a bad scan of any kind, or a succesful scan. If scan
+  // is successful, |recognized_user_ids| will equal all the enrollment IDs
+  // that match the scan.
+  OnAttempt(uint32 scan_result, array<string> recognized_user_ids);
+
+  // Called during either mode to indicate a failure. Any enrollment that was
+  // underway is thrown away and authentication will no longer be happening.
+  OnFailure();
+};
+
+// Interface for communicating with biod through dbus.
+interface Fingerprint {
+  // Gets all the enrollments registered with this biometric.
+  GetFingerprintsList() => (array<string> enrollments);
+
+  // Starts the biometric enrollment.
+  StartEnroll(string user_id, string label);
+
+  // Ends the current enroll.
+  CancelCurrentEnroll();
+
+  // Gets label of the enrollment.
+  GetLabel(int32 index) => (string label);
+
+  // Changes the label of the enrollment to |label|.
+  SetLabel(string label, int32 index);
+
+  // Removes the enrollment. This enrollment will no longer
+  // be able to used for authentication.
+  RemoveEnrollment(int32 index);
+
+  // Starts the biometric authentication.
+  StartAuthentication();
+
+  // Ends the current autentication.
+  EndCurrentAuthentication();
+
+  // Irreversibly destroys all enrollments registered with this biometric.
+  DestroyAllEnrollments();
+
+  // Add biod observers and notify them when receiving signals.

[blundell, 2017/02/22 15:20:08]

nit: Adds ... and notifies

[xiaoyinh(OOO Sep 11-29), 2017/02/22 21:03:17]

Done.

+  AddBiodObserver(BiodObserver observer);
+};
+