extensions: tabs: set tab id to -1 for app/devtools windows

chrome/test/data/extensions/api_test/tabs/no_events/test.js

+// 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.
+
+var errors = 0;
+
+function errorListener() { ++errors; }
+
+chrome.tabs.onCreated.addListener(errorListener);
+chrome.tabs.onRemoved.addListener(errorListener);
+chrome.tabs.onUpdated.addListener(errorListener);
+
+chrome.test.sendMessage('ready', function (message) {
+  if (errors == 0)
+    chrome.test.notifyPass();
+  else
+    chrome.test.notifyFail('Unexpected chrome.tabs events');
+});