Final cleanup pass over audio device API

extensions/test/data/api_test/audio/volume_change/background.js

Index: extensions/test/data/api_test/audio/volume_change/background.js
diff --git a/extensions/test/data/api_test/audio/volume_change/background.js b/extensions/test/data/api_test/audio/volume_change/background.js
index 7c6a845c9192bf1ff248562b22f7139f3ce264f6..1e54042fd7a380d498b1ba992d8fa303a414a1b6 100644
--- a/extensions/test/data/api_test/audio/volume_change/background.js
+++ b/extensions/test/data/api_test/audio/volume_change/background.js
@@ -4,9 +4,9 @@
 
 chrome.test.runTests([
   function waitForLevelChangedEventTests() {
-    chrome.test.listenOnce(chrome.audio.OnLevelChanged, function (id, level) {
-      chrome.test.assertEq('30001', id);
-      chrome.test.assertEq(60, level);
+    chrome.test.listenOnce(chrome.audio.onLevelChanged, function (evt) {
+      chrome.test.assertEq('30001', evt.deviceId);
+      chrome.test.assertEq(60, evt.level);
     });
   }
 ]);