bluetooth: Add basic scanning to chrome://bluetooth-internals.

device/bluetooth/public/interfaces/adapter.mojom

 // Copyright 2016 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;
 
 import "device/bluetooth/public/interfaces/device.mojom";
 
 // Possible errors sent as a response by Adapter.ConnectToDevice on a Device
 // connection request.
@@ skipping 21 matching lines @@
 struct AdapterInfo {
   string address;
   string name;
   bool initialized;
   bool present;
   bool powered;
   bool discoverable;
   bool discovering;
 };
 
+interface DiscoverySession {
+  // Returns true if the session is active, false otherwise. If false, the
+  // adapter might still be discovering as there might still be other active
+  // sessions; this just means that this instance no longer has a say in
+  // whether or not discovery should continue. In this case, a new
+  // DiscoverySession should be started to make sure that device discovery
+  // continues.
+  IsActive() => (bool active);
+
+  // Requests this discovery session instance to stop. If this instance is
+  // active, the session will stop. Returns false if this session is inactive.
+  Stop() => (bool success);

[scheib, 2017/01/05 01:02:20]

Copy more of the comment from bluetooth_discovery_session.h noting that stopping
a session only stops discovery if it was the only session. 

The result of an error isn't well defined, is it really just telling us if
IsActive was true? In that case, we don't need the return value. But, if there
are other errors in stopping then the documentation here is a bit misleading as
it currently implies the return value is only about weather the session was
active.

[mbrunson, 2017/01/05 01:19:14]

Ok. I've copied the original comment from bluetooth_discovery_session and
tweaked it a little. Done.

+};
+
 interface Adapter {
-  // Gets basic information about the adapter.
-  GetInfo() => (AdapterInfo info);
-
   // Creates a GATT connection to the device with |address| and returns a
   // Device if the connection was succesful. The GATT connection is tied to the
   // the lifetime of the Device message pipe.
   ConnectToDevice(string address) => (ConnectResult result, Device? device);
 
   // Retrieves the list of the devices known by the adapter including Connected
   // Devices, GATT Connected Devices, Paired Devices and Devices discovered
   // during a classic or low-energy scan.
   GetDevices() => (array<DeviceInfo> devices);
 
+  // Gets basic information about the adapter.
+  GetInfo() => (AdapterInfo info);
+
   // Sets the client that listens for the adapter's events.
   SetClient(AdapterClient client);
+
+  // Requests the adapter to start a new discovery session. Returns null if
+  // session not created successfully.
+  StartDiscoverySession() => (DiscoverySession? session);
 };
 
 interface AdapterClient {
+  // Called when the discovering state of the adapter changes.
+  DiscoveringChanged(bool discovering);
+
   // Called the first time a device is discovered.
   DeviceAdded(DeviceInfo device);
 
-  // Called after the device hasn't been seen for 3 minutes.
-  DeviceRemoved(DeviceInfo device);
-
   // Called when one of the following properties of a device changes:
   //   Address, appearance, Bluetooth class, Inquiry RSSI, Inquiry TX Power,
   //   Service UUIDs, Connectionable state, Connection state, Pairing state,
   //   Trustable state.
   // Generally called for each advertisement packet recevied, but this is not
   // guaranteed on ChromeOS or Linux. Because the RSSI is always changing,
   // it's very likely this will be called for each advertising packet.
   DeviceChanged(DeviceInfo device);
+
+  // Called after the device hasn't been seen for 3 minutes.
+  DeviceRemoved(DeviceInfo device);
+
 };
 
 interface AdapterFactory {
   // Gets an Adapter interface. Returns null if Bluetooth is not supported.
   GetAdapter() => (Adapter? adapter);
 };