bluetooth: Add device list retrieval for chrome://bluetooth-internals

chrome/browser/resources/bluetooth_internals/bluetooth_internals.js

 // 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.
 
 /**
  * Javascript for bluetooth_internals.html, served from
  *     chrome://bluetooth-internals/.
  */
 
-document.addEventListener('DOMContentLoaded', function() {
-  console.log('Welcome to Bluetooth Internals.');
-});
+/**
+ * The implementation of AdapterClient in
+ *     device/bluetooth/public/interfaces/adapter.mojom.
+ */
+var AdapterClient = function() {};
+AdapterClient.prototype = {
+  /**
+   * Prints added device to console.
+   * @param {!Object} device the device that was added
+   */
+  deviceAdded: function(device) {
+    console.log('Device added');

[dpapad, 2016/10/03 17:51:03]

Are those console.logs temporary?

[mbrunson, 2016/10/03 18:56:03]

Yes. They are temporary.

+    console.log(device);
+  },
+
+  /**
+   * Prints removed device to console.
+   * @param {!Object} device the device that was removed
+   */
+  deviceRemoved: function(device) {
+    console.log('Device removed');
+    console.log(device);
+  }
+};
+
+(function() {
+  var adapter = null;
+  var adapterClient = null;
+  var adapterClientHandle = null;
+
+  /**
+   * Helper to convert callback-based define() API to a promise-based API.
+   * @param {!Array<string>} moduleNames
+   * @return {!Promise}
+   */
+  function importModules(moduleNames) {

[dpapad, 2016/10/03 17:51:03]

This function is repeated 3 times (and now 4), across the codebase, see
https://cs.chromium.org/search/?q=importModules+lang:js&sq=package:chromium&t....
We should probably put it in as shared location and re-use. Can you add a TODO
and/or file a bug about this, so that we don't loose track?

[mbrunson, 2016/10/03 18:56:02]

I've made a bug for this and added a TODO: crbug.com/652361

+    return new Promise(function(resolve, reject) {
+      define(moduleNames, function(var_args) {
+        resolve(Array.prototype.slice.call(arguments, 0));
+      });
+    });
+  }
+
+  /**
+   * Initializes Mojo proxies for page and Bluetooth services.
+   * @return {!Promise}
+   */
+  function initializeProxies() {
+    return importModules([
+             'content/public/renderer/frame_interfaces',

[dpapad, 2016/10/03 17:51:03]

Indentation seems quite a bit off here. Shouldn't it be as follows?

return importModules([
  'content/public/renderer/frame_interfaces',
  ...
]).then(function(modules) {
  ...
});

[mbrunson, 2016/10/03 18:56:02]

Done.

+             'device/bluetooth/public/interfaces/adapter.mojom',
+             'mojo/public/js/connection',
+           ])
+        .then(function(modules) {
+          var frameInterfaces = modules[0];

[dpapad, 2016/10/03 17:51:03]

Nit: I believe that you can use destructuring assignment now
(https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/D...)

var frameInterfaces, bluetoothAdapter, connection;
[frameInterfaces, bluetoothAdapter, connection] = modules;

[mbrunson, 2016/10/03 18:56:03]

Done.

+          var bluetoothAdapter = modules[1];
+          var connection = modules[2];
+
+          console.log('Loaded modules');
+
+          // Hook up the instance properties
+          AdapterClient.prototype.__proto__ =
+              bluetoothAdapter.AdapterClient.stubClass.prototype;
+
+          // Create a message pipe and bind one end to client
+          // implementation

[dpapad, 2016/10/03 17:51:03]

Nit: Comments should have proper punctuation.

[mbrunson, 2016/10/03 18:56:02]

Done.

+          adapterClient = new AdapterClient();
+          adapterClientHandle = connection.bindStubDerivedImpl(adapterClient);
+
+          adapter = connection.bindHandleToProxy(
+              frameInterfaces.getInterface(bluetoothAdapter.Adapter.name),
+              bluetoothAdapter.Adapter);
+
+          adapter.setClient(adapterClientHandle);
+        });
+  }
+
+  document.addEventListener('DOMContentLoaded', function() {
+    initializeProxies()
+        .then(function() { return adapter.getDevices();})
+        .then(function(response) {console.log(response.devices);});
+  });
+})();