bluetooth: Add FakeBluetooth interface

device/bluetooth/test/README.md

-# Bluetooth
+# Testing
 
-`device/bluetooth` abstracts
-[Bluetooth Classic](https://en.wikipedia.org/wiki/Bluetooth) and
-[Low Energy](https://en.wikipedia.org/wiki/Bluetooth_low_energy) features
-across multiple platforms.
-
-Classic and Low Energy based profiles differ substantially. Platform
-implementations may support only one or the other, even though several classes
-have interfaces for both, e.g. `BluetoothAdapter` & `BluetoothDevice`.
-
-|           | Classic |  Low Energy |
-|-----------|:-------:|:-----------:|
-| Android   |   no    |     yes     |
-| Chrome OS |   yes   |     yes     |
-| Linux     |   yes   |     yes     |
-| Mac       |   yes   |     yes     |
-| Windows   |   some  |    nearly   |
-
-Chrome OS and Linux are supported via BlueZ, see `*_bluez` files.
-
-[Mojo](https://www.chromium.org/developers/design-documents/mojo)
-interfaces in [public/interfaces](public/interfaces) have been started
-but are *not* ready for production use.
-
-
-## Maintainer History
-
-Initial implementation OWNERS were youngki@chromium.org, keybuk@chromium.org,
-armansito@chromium.org, and rpaquay@chromium.org. They no longer contribute to
-chromium fulltime. They were responsible for support for Chrome OS Bluetooth
-features and the Chrome Apps APIs:
-
-* [chrome.bluetooth](https://developer.chrome.com/apps/bluetooth)
-* [chrome.bluetoothLowEnergy](https://developer.chrome.com/apps/bluetoothLowEnergy)
-* [chrome.bluetoothSocket](https://developer.chrome.com/apps/bluetoothSocket)
-
-Active development in 2015 & 2016 is focused on enabling GATT features for:
-
-* [Web Bluetooth](https://crbug.com/419413)
-* Peripheral mode for Chrome OS.
-
-Known future work is tracked in the
-[Refactoring meta issue](https://crbug.com/580406).
-
-
-## Testing
-
 Implementation of the Bluetooth component is tested via unittests. Client code
 uses Mock Bluetooth objects:
 
+## Mojo Testing Interface Implementation
+See [//public/interfaces/test/README.md](//device/bluetooth/public/interfaces/test/README.md)
+for details about the interface. The current implementation of this interface
+creates a fake implementation of the current non-mojo C++ Bluetooth interface.
+This interface is implemented across files with a "fake_" prefix.
+*This interface may be removed when a Bluetooth Mojo Service is introduced, if
+Web Bluetooth remains its only client. Testing code would implement the service
+as needed for tests.*
 
-### Cross Platform Unit Tests
+## Cross Platform Unit Tests
 
 New feature development uses cross platform unit tests. This reduces test code
 redundancy and produces consistency across all implementations.
 
 Unit tests operate at the public `device/bluetooth` API layer and the
 `BluetoothTest` fixture controls fake operating system behavior as close to the
 platfom as possible. The resulting test coverage spans the cross platform API,
 common implementation, and platform specific implementation as close to
 operating system APIs as possible.
 
 `test/bluetooth_test.h` defines the cross platform test fixture
 `BluetoothTestBase`. Platform implementations provide subclasses, such as
 `test/bluetooth_test_android.h` and typedef to the name `BluetoothTest`.
 
 [More testing information](https://docs.google.com/document/d/1mBipxn1sJu6jMqP0RQZpkYXC1o601bzLCpCxwTA2yGA/edit?usp=sharing)
 
-### Legacy Platform Specific Unit Tests
+## Legacy Platform Specific Unit Tests
 
 Early code (Classic on most platforms, and Low Energy on BlueZ) was tested with
 platform specific unit tests, e.g. `bluetooth_bluez_unittest.cc` &
 `bluetooth_adapter_win_unittest.cc`. The BlueZ style has platform specific
 methods to create fake devices and the public API is used to interact with them.
 
 Maintenance of these earlier implementation featuress should update tests in
 place. Long term these tests should be [refactored into cross platform
 tests](https://crbug.com/580403).
 
 
-### Mock Bluetooth Objects
+## Mock Bluetooth Objects
 
 `test/mock_bluetooth_*` files provide GoogleMock based fake objects for use in
 client code.
 
 
-### Chrome OS Blueooth Controller Tests
+## Chrome OS Blueooth Controller Tests
 
 Bluetooth controller system tests generating radio signals are run and managed
 by the Chrome OS team. See:
 https://chromium.googlesource.com/chromiumos/third_party/autotest/+/master/server/site_tests/
 https://chromium.googlesource.com/chromiumos/third_party/autotest/+/master/server/cros/bluetooth/
 https://chromium.googlesource.com/chromiumos/third_party/autotest/+/master/client/cros/bluetooth/
 
 
-## Android
+# Android
 
 The android implementation requires crossing from C++ to Java using
 [__JNI__](https://www.chromium.org/developers/design-documents/android-jni).
 
 Object ownership is rooted in the C++ classes, starting with the Adapter, which
 owns Devices, Services, etc. Java counter parts interface with the Android
 Bluetooth objects. E.g.
 
 For testing, the Android objects are __wrapped__ in:
 `android/java/src/org/chromium/device/bluetooth/Wrappers.java`. <br>
@@ skipping 14 matching lines @@
             * `android/.../ChromeBluetoothService.java` uses:
                 * `android/.../Wrappers.java`: `BluetoothServiceWrapper`
                     * Which under test is a `FakeBluetoothService`
             * ... and so on for characteristics and descriptors.
 
 Fake objects are controlled by `bluetooth_test_android.cc`.
 
 See also: [Class Diagram of Web Bluetooth through Bluetooth Android][Class]
 
 [Class]: https://sites.google.com/a/chromium.org/dev/developers/design-documents/bluetooth-design-docs/web-bluetooth-through-bluetooth-android-class-diagram
-
-
-## Design Documents
-
-* [Bluetooth Notifications](https://docs.google.com/document/d/1guBtAnQUP8ZoZre4VQGrjR5uX0ZYxfK-lwKNeqY0-z4/edit?usp=sharing) 2016-08-26
-    * Web Bluetooth through Android implementation details, class diagram and
-      call flow.