Add hook for extension to check sync status.

chrome/test/data/extensions/api_test/preferences_private/test.js

Index: chrome/test/data/extensions/api_test/preferences_private/test.js
diff --git a/chrome/test/data/extensions/api_test/preferences_private/test.js b/chrome/test/data/extensions/api_test/preferences_private/test.js
new file mode 100644
index 0000000000000000000000000000000000000000..06510587f47d657a385f3a15805874ee88c882d0
--- /dev/null
+++ b/chrome/test/data/extensions/api_test/preferences_private/test.js
@@ -0,0 +1,25 @@
+// Copyright 2013 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.
+
+chrome.test.runTests([function() {
+  chrome.preferencesPrivate.getSyncCategoriesWithoutPassphrase(
+    function(categories) {

[not at google - send to devlin, 2013/12/18 22:30:37]

use chrome.test.callbackPass(function(categories) { ... })

[Rune Fevang, 2013/12/19 00:13:43]

Done.

+      var bookmarks_found = false;
+      var preferences_found = false;
+      for (var i = 0; i < categories.length; i++) {
+        if (categories[i] === "Bookmarks")
+          bookmarks_found = true;
+        else if (categories[i] === "Preferences")
+          preferences_found = true;
+        else if (categories[i] === "Autofill")
+          chrome.test.fail("Autofill present even though it's encrypted");
+        else if (categories[i] === "Typed URLs")
+          chrome.test.fail("Typed URLs present even though it's not synced");
+      }

[not at google - send to devlin, 2013/12/18 22:30:37]

Could you do like:

chrome.test.assertTrue(categories.indexOf("Bookmarks") >= 0, "bookmarks is
missing");
chrome.test.assertTrue(categories.indexOf("Preferences") >= 0, "preferences is
missing");
chrome.test.assertEq(2, categories.length, "unexpected categories");

[Rune Fevang, 2013/12/19 00:13:43]

Done, except I don't want to make any assumptions on how many categories there
are here.

+      chrome.test.assertTrue(bookmarks_found, "Bookmarks is missing.");
+      chrome.test.assertTrue(preferences_found, "Preferences is missing.");
+      chrome.test.succeed();

[not at google - send to devlin, 2013/12/18 22:30:37]

... and you won't need the succeed() at the end here.

[Rune Fevang, 2013/12/19 00:13:43]

Done.

+    }
+  );
+}]);