bluetooth: Basic browser tests for chrome://bluetooth-internals.

chrome/browser/resources/bluetooth_internals/interfaces.js

Index: chrome/browser/resources/bluetooth_internals/interfaces.js
diff --git a/chrome/browser/resources/bluetooth_internals/interfaces.js b/chrome/browser/resources/bluetooth_internals/interfaces.js
index 3b243097a542f9c8e7c18e808dab958c391b9878..b2c26c56efa775d204cc97ac47c571b6b3eed54f 100644
--- a/chrome/browser/resources/bluetooth_internals/interfaces.js
+++ b/chrome/browser/resources/bluetooth_internals/interfaces.js
@@ -64,23 +64,15 @@ cr.define('interfaces', function() {
     });
   }
 
-  var initialized = false;
-  var initializePromise = null;
+  /**
+  * Overriden by tests to give them a chance to setup a fake Mojo browser proxy
+  * before any other code executes.
+  * @return {!Promise} A promise firing once necessary setup has been completed.
+  */
+  var setupFn = window.setupFn || function() { return Promise.resolve(); };
 
   function initialize() {
-    if (initialized) {
-      return Promise.resolve();
-    }
-
-    if (initializePromise) {
-      return initializePromise;
-    }
-
-    initializePromise = initializeProxies().then(function() {
-      initialized = true;
-    });
-
-    return initializePromise;
+    return setupFn().then(initializeProxies);
   }
 
   return {