Revert of Add the chrome.fileSystem.onVolumeListChanged event.

chrome/test/data/extensions/api_test/file_system/on_volume_list_changed/background.js

Index: chrome/test/data/extensions/api_test/file_system/on_volume_list_changed/background.js
diff --git a/chrome/test/data/extensions/api_test/file_system/on_volume_list_changed/background.js b/chrome/test/data/extensions/api_test/file_system/on_volume_list_changed/background.js
deleted file mode 100644
index 2dba1c3ecd4012bc83ff296548bc51f3c3ff6f7c..0000000000000000000000000000000000000000
--- a/chrome/test/data/extensions/api_test/file_system/on_volume_list_changed/background.js
+++ /dev/null
@@ -1,27 +0,0 @@
-// Copyright 2015 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.
-
-function runTests() {
-  chrome.test.runTests([
-    function onVolumeListChanged() {
-      chrome.fileSystem.getVolumeList(
-         chrome.test.callbackPass(function(volumeList) {
-           chrome.test.assertEq(4, volumeList.length);
-
-           // Confirm that adding a newly mounted volume emits an event, and
-           // that the volume list is updated.
-           chrome.fileSystem.onVolumeListChanged.addListener(
-               chrome.test.callbackPass(function(event) {
-                 chrome.test.assertEq(5, event.volumes.length);
-                 chrome.fileSystem.getVolumeList(
-                     chrome.test.callbackPass(function(volumeList) {
-                       chrome.test.assertEq(5, volumeList.length);
-                     }));
-               }));
-      }));
-    }
-  ]);
-}
-
-chrome.app.runtime.onLaunched.addListener(runTests);