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) {

[David Tseng, 2014/05/29 22:41:31]

This almost makes me want named object parameters (e.g.
getTree({tabID: tab.id})

Or the getTree function should be named getTab to make that clear.

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

What other named parameters might we want? I'm definitely up for doing this if
there's more than one, but tabID is the only one I can think of.
I'm still ok with getTree - if you look at it in context in the tests, it's
either

chrome.automation.getTree(function(tree) { ... })

or

chrome.automation.getTree(tab.id, function(tree) { ... })

so particularly in the tabId case it's pretty clear that it's on a per-tab
basis. I think getTab() would be confusing as it's not retrieving a Tab object;
getTreeForTab() would be confusing if we're not requesting it by tabId.

+              var title = tree.root.attributes['docTitle'];

[David Tseng, 2014/05/29 22:41:31]

nit: attributes.docTitle

+              chrome.test.assertEq('Automation Tests', title);
+              chrome.test.succeed();
+            });
+          });
+        });
+      });
+    });
+  }
+];
+
+chrome.test.runTests(allTests);