Update more extension manifests to manifest_version 2

chrome/test/data/extensions/devtools/timeline_api_two/background_two.js

+// 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.
+
+var devtoolsTabEvents = undefined;
+
+function pageEventListener() {
+  receivedEvents.push("onPageEvent");
+}
+
+function tabCloseListener() {
+  receivedEvents.push("onTabClose");
+}
+
+function registerListenersForTab(tabId) {
+  devtoolsTabEvents = chrome.devtools.getTabEvents(tabId);
+  devtoolsTabEvents.onPageEvent.addListener(pageEventListener);
+  devtoolsTabEvents.onTabClose.addListener(tabCloseListener);
+  window.domAutomationController.send(true);
+}
+
+function unregisterListeners() {
+  devtoolsTabEvents.onPageEvent.removeListener(pageEventListener);
+  devtoolsTabEvents.onTabClose.removeListener(tabCloseListener);
+  window.domAutomationController.send(true);
+}