bluetooth: Add FakeBluetooth interface

device/bluetooth/public/interfaces/test/fake_bluetooth.mojom

+// 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 bluetooth.mojom;
+
+// FakeBluetooth allows its clients to fake the global Bluetooth state.

[scheib, 2017/04/08 00:59:50]

Let's create a src/device/bluetooth/public/interfaces/test/README.md and as
important elements of the design are implemented add the design details to it.
It may remain very small, but READMEs are good.

[ortuno, 2017/04/10 01:47:49]

I really dislike the idea of a small README because chances are we are going to
forget about it and its going to rot very easily. Furthermore I don't think a
README for this might be worth it since it's pretty much just throwaway code.

[scheib, 2017/04/10 21:52:31]

I'd like to see:
a) Relevant design documentation that lives in the code. Here or up at
device/bluetooth is fine. Yes, docs can rot -- so lets try to not have that
happen. By including in code we're more likely to keep them fresh vs a one-off
external design doc.

b) People be able to discover the docs. If I come to a public/interfaces folder
I expect those interfaces to be described at a high level so that client code
can be understood. Docs inline here, pointing to a device/bluetooth doc, or
adjacent in a READEME.md would all satisfy that.

[ortuno, 2017/04/12 05:49:06]

OK. I added a README to bluetooth/public/interfaces/test that points to
fake_bluetooth.mojom for more information about the interface and
device/bluetooth/test/README.md for more information about the implementation.
Do you think that's OK? I tried to decouple the implementation details from the
interface given that the implementation details are more likely to change.

+interface FakeBluetooth {
+  // Set to false to simulate that the platform doesn't support Bluetooth Low
+  // Energy.
+  SetLEAvailability(bool available) => ();
+};