bluetooth: Standardize Bluetooth adapter access in Adapter service.

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;
 
 struct DeviceInfo {
   string? name;
   string name_for_display;
   string id;
@@ skipping 10 matching lines @@
   SetClient(AdapterClient client);
 };
 
 interface AdapterClient {
   // 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);
 };
+
+interface AdapterFactory {
+  // Gets an adapter interface.
+  GetAdapter(Adapter& adapter, AdapterClient client) => (bool success);

[ortuno, 2016/10/05 02:07:51]

I think the following interface would simplify things a bit:

GetAdapter() => (Adapter? adapter);

That would result in the following js:

return adapterFactory.getAdapter().then(function(response) {
  if (!response.adapter) {
    throw 'Bluetooth Not Supported on this platform.';
  }
  adapter = connection.bindHandleProxy(
    response.adapter,
    bluetoothAdapter.Adapter);

  adapterClient = new AdapterClient();
  adapter.setClient(connection.bindStubDerivedImpl(adapterClient));
});

WDYT?

[mbrunson, 2016/10/05 17:59:04]

That makes sense. It's easier to follow in my opinion.

+};