bluetooth: Add Device connection logic and accompanying user interface.

chrome/browser/resources/bluetooth_internals/adapter_broker.js

Index: chrome/browser/resources/bluetooth_internals/adapter_broker.js
diff --git a/chrome/browser/resources/bluetooth_internals/adapter_broker.js b/chrome/browser/resources/bluetooth_internals/adapter_broker.js
index c17c89fe2a4806ce63a0155d4f5fba024ef10c33..7f27d8f902bb35735ab62a3cbd1a091362e67691 100644
--- a/chrome/browser/resources/bluetooth_internals/adapter_broker.js
+++ b/chrome/browser/resources/bluetooth_internals/adapter_broker.js
@@ -27,6 +27,30 @@ cr.define('adapter_broker', function() {
     __proto__: cr.EventTarget.prototype,
 
     /**
+     * Creates a GATT connection to the device with |address|.
+     * @param {string} address
+     * @return {Promise<interfaces.BluetoothDevice.Device.proxyClass>}
+     */
+    connectToDevice: function(address) {
+      return this.adapter_.connectToDevice(address).then(function(response) {
+        if (response.result !=
+            interfaces.BluetoothAdapter.ConnectResult.SUCCESS) {
+          // TODO(crbug.com/663394): Replace with more descriptive error
+          // messages.
+          var errorString = Object.keys(
+              interfaces.BluetoothAdapter.ConnectResult)[response.result];
+
+          throw new Error(errorString);
+        }
+
+        response.device = interfaces.Connection.bindHandleToProxy(
+            response.device,
+            interfaces.BluetoothDevice.Device);
+        return response;

[ortuno, 2016/11/09 03:24:03]

Why not return just the device?

[mbrunson, 2016/11/09 23:39:37]

Done.

+      });
+    },
+
+    /**
      * Sets client of Adapter service.
      * @param {interfaces.BluetoothAdapter.AdapterClient} adapterClient
      */