Revert 127833 - Re-land alexbost's experimental offscreenTabs API.

chrome/test/data/extensions/api_test/offscreen_tabs/tab_util.js

-// Copyright (c) 2012 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.
-
-var pass = chrome.test.callbackPass;
-var fail = chrome.test.callbackFail;
-var assertEq = chrome.test.assertEq;
-var assertTrue = chrome.test.assertTrue;
-var assertFalse = chrome.test.assertFalse;
-
-var Q_KEY = 113;
-
-function assertEqTabs(tab1, tab2) {
-  assertEq(tab1.id, tab2.id);
-  assertSimilarTabs(tab1, tab2);
-}
-
-function maybeExpandURL(url) {
-  if (url.match('chrome-extension'))
-    return url;
-  return chrome.extension.getURL(url);
-}
-
-function assertSimilarTabs(tab1, tab2) {
-  assertEq(maybeExpandURL(tab1.url), maybeExpandURL(tab2.url));
-  assertEq(tab1.width, tab2.width);
-  assertEq(tab1.height, tab2.height);
-}
-
-function assertTabDoesNotExist(tabId) {
-  var expectedError = 'No offscreen tab with id: ' + tabId + '.';
-  chrome.experimental.offscreenTabs.get(tabId, fail(expectedError));
-}
-
-function getBaseMouseEvent() {
-  return {
-    button: 0,
-    altKey: false,
-    ctrlKey: false,
-    shiftKey: false
-  };
-};
-
-function getKeyboardEvent(keyCode) {
-  return {
-    type: 'keypress',
-    charCode: keyCode,
-    keyCode: keyCode,
-    altKey: false,
-    ctrlKey: false,
-    shiftKey: false
-  };
-}