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

device/bluetooth/public/interfaces/adapter.mojom

Index: device/bluetooth/public/interfaces/adapter.mojom
diff --git a/device/bluetooth/public/interfaces/adapter.mojom b/device/bluetooth/public/interfaces/adapter.mojom
index 50042ae7a27e94750df7fc1c09967588dcf20f58..88c0f92d86fcd4f6a60258098cf953e7b24782a3 100644
--- a/device/bluetooth/public/interfaces/adapter.mojom
+++ b/device/bluetooth/public/interfaces/adapter.mojom
@@ -39,10 +39,21 @@ struct AdapterInfo {
   bool discovering;
 };
 
-interface Adapter {
-  // Gets basic information about the adapter.
-  GetInfo() => (AdapterInfo info);
+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 {
   // 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.
@@ -53,17 +64,24 @@ interface Adapter {
   // 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,
@@ -72,6 +90,10 @@ interface AdapterClient {
   // 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 {