bluetooth: Standardize Bluetooth adapter access in Adapter service.

chrome/browser/resources/bluetooth_internals/bluetooth_internals.js

Index: chrome/browser/resources/bluetooth_internals/bluetooth_internals.js
diff --git a/chrome/browser/resources/bluetooth_internals/bluetooth_internals.js b/chrome/browser/resources/bluetooth_internals/bluetooth_internals.js
index 23f02c3329b4a650c37ba5233bcaae368860b965..2c8753ad1b5bf7816247a809b76196e7ddad9ef3 100644
--- a/chrome/browser/resources/bluetooth_internals/bluetooth_internals.js
+++ b/chrome/browser/resources/bluetooth_internals/bluetooth_internals.js
@@ -33,9 +33,9 @@ AdapterClient.prototype = {
 };
 
 (function() {
+  var adapterFactory = null;
   var adapter = null;
   var adapterClient = null;
-  var adapterClientHandle = null;
 
   /**
    * TODO: Move to shared location. See crbug.com/652361.
@@ -53,7 +53,7 @@ AdapterClient.prototype = {
 
   /**
    * Initializes Mojo proxies for page and Bluetooth services.
-   * @return {!Promise}
+   * @return {!Promise} resolves if adapter is acquired

[dpapad, 2016/10/06 00:52:45]

Nit: Use proper punctuation (per styleguide). Also the comment makes it sound
that the Promise is never fulfilled otherwise (fulfill = resolve OR reject).
Let's rephrase to indicate that it rejects if bluetooth is not supported.

[mbrunson, 2016/10/06 01:13:58]

Done.

    */
   function initializeProxies() {
     return importModules([
@@ -67,22 +67,31 @@ AdapterClient.prototype = {
       AdapterClient.prototype.__proto__ =
           bluetoothAdapter.AdapterClient.stubClass.prototype;
 
-      // Create a message pipe and bind one end to client
-      // implementation.
-      adapterClient = new AdapterClient();
-      adapterClientHandle = connection.bindStubDerivedImpl(adapterClient);
+      adapterFactory = connection.bindHandleToProxy(

[dpapad, 2016/10/06 00:52:45]

Does this need to be global? It is only used within this scope. Can we just do
the following?

var adapterFactory = ...;

[mbrunson, 2016/10/06 01:13:58]

Done.

+          frameInterfaces.getInterface(bluetoothAdapter.AdapterFactory.name),
+          bluetoothAdapter.AdapterFactory);
+
+      // Get an Adapter service.
+      return adapterFactory.getAdapter().then(function(response) {
+          if (!response.adapter) {
+            throw new Error('Bluetooth Not Supported on this platform.');
+          }
 
-      adapter = connection.bindHandleToProxy(
-          frameInterfaces.getInterface(bluetoothAdapter.Adapter.name),
-          bluetoothAdapter.Adapter);
+          adapter = connection.bindHandleToProxy(response.adapter,
+                                                 bluetoothAdapter.Adapter);
 
-      adapter.setClient(adapterClientHandle);
+          // Create a message pipe and bind one end to client
+          // implementation and the other to the Adapter service.
+          adapterClient = new AdapterClient();
+          adapter.setClient(connection.bindStubDerivedImpl(adapterClient));
+      });
     });
   }
 
   document.addEventListener('DOMContentLoaded', function() {
     initializeProxies()
       .then(function() { return adapter.getDevices(); })
-      .then(function(response) { console.log(response.devices); });
+      .then(function(response) { console.log(response.devices); })
+      .catch(function(error) { console.error(error); });
   });
 })();