Allow requesting Automation tree by tabId

chrome/test/data/extensions/api_test/automation/tests/tabs/tab_id.js

+// Copyright 2014 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 allTests = [
+  function testGetTabById() {
+    chrome.tabs.query({ active: true }, function(tabs) {
+      chrome.test.assertEq(1, tabs.length);
+      var newTabPageTab = tabs[0];
+      getUrlFromConfig(function(url) {
+        createTab(url, function(tab) {
+          // make the NTP the active tab so that we know we're requesting the
+          // tab by ID rather than just getting the active tab still.
+          chrome.tabs.update(newTabPageTab.id, { active: true }, function() {
+            chrome.automation.getTree(tab.id, function(tree) {
+              tree.addEventListener('loadComplete', function() {
+                var title = tree.root.attributes['docTitle'];
+                chrome.test.assertEq('Automation Tests', title);
+                chrome.test.succeed();
+              });

[not at google - send to devlin, 2014/05/29 22:41:37]

impressive

you should really be wrapping these callback (in fact, all callbacks from an
extension function result) in chrome.test.callbackPass, and unfortunately that
would make everything... so much worse. are there functions you can pull some of
this stuff into? I see you have "createTab"; it seems like the "get active tab
and fetch config" stuff could be some kind of initialization?

[aboxhall, 2014/05/30 15:37:11]

How do you mean functions I could pull this stuff into? They'd be one-offs... I
could pull the functions up into the main function and then call them by
name...?

[aboxhall, 2014/05/30 16:09:16]

Done (after offline discussion).

+            })
+          });
+        });
+      });
+    });
+  }
+];
+
+chrome.test.runTests(allTests);