Move another bunch of extension API tests to manifest_version 2.

chrome/test/data/extensions/api_test/clear/one_at_a_time/background.html

-<script>
-  var allTypes = {
-    cache: true,
-    cookies: true,
-    downloads: true,
-    formData: true,
-    history: true,
-    passwords: true
-  };
-  chrome.test.runTests([
-    function testEverything() {
-      chrome.experimental.clear.browsingData("everything", allTypes,
-          chrome.test.callbackFail(
-              'Only one \'clear\' API call can run at a time.'));
-    },
-    function testClearCache() {
-      chrome.experimental.clear.cache("everything",
-          chrome.test.callbackFail(
-              'Only one \'clear\' API call can run at a time.'));
-    },
-    function testClearCookies() {
-      chrome.experimental.clear.cookies("everything",
-          chrome.test.callbackFail(
-              'Only one \'clear\' API call can run at a time.'));
-    },
-    function testClearHistory() {
-      chrome.experimental.clear.history("everything",
-          chrome.test.callbackFail(
-              'Only one \'clear\' API call can run at a time.'));
-    },
-    function testClearPasswords() {
-      chrome.experimental.clear.passwords("everything",
-          chrome.test.callbackFail(
-              'Only one \'clear\' API call can run at a time.'));
-    },
-    function testClearDownloads() {
-      chrome.experimental.clear.downloads("everything",
-          chrome.test.callbackFail(
-              'Only one \'clear\' API call can run at a time.'));
-    },
-    function testClearFormData() {
-      chrome.experimental.clear.formData("everything",
-          chrome.test.callbackFail(
-              'Only one \'clear\' API call can run at a time.'));
-    }
-  ]);
-</script>
+<!--
+ * Copyright (c) 2011 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.
+-->
+<script src="background.js"></script>