[Extensions] Expose enums on extension APIs.

chrome/test/data/extensions/api_test/bindings/api_enums/background.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.
+
+chrome.test.runTests([
+  function() {
+    // Test management (backed by a json file) api enums.
+
+    // The enum should be declared on the API object.
+    chrome.test.assertTrue(
+        'LaunchType' in chrome.management,
+        '"LaunchType" is not present on chrome.management.');
+    // The object should have entries for each enum entry. Note that we don't
+    // test all entries here because we don't want to update this test if the
+    // management api changes.
+    chrome.test.assertTrue(
+        'OPEN_AS_REGULAR_TAB' in chrome.management.LaunchType,
+        '"OPEN_AS_REGULAR_TAB" is not present on management.LaunchType');
+    // The value of the enum should be its string value.
+    chrome.test.assertEq(chrome.management.LaunchType.OPEN_AS_REGULAR_TAB,
+                         'OPEN_AS_REGULAR_TAB');
+    // There should be more than one value for the enum.
+    chrome.test.assertTrue(
+        Object.keys(chrome.management.LaunchType).length > 1);
+
+    // Perform an analogous test for the notifications api (backed by an idl).
+    chrome.test.assertTrue(
+        'PermissionLevel' in chrome.notifications,
+        '"PermissionLevel" is not present on chrome.notifications.');
+    chrome.test.assertTrue(
+        'granted' in chrome.notifications.PermissionLevel,
+        '"granted" is not present on notifications.PermissionLevel');
+    chrome.test.assertEq(chrome.notifications.PermissionLevel.granted,
+                         'granted');
+    chrome.test.assertTrue(
+        Object.keys(chrome.notifications.PermissionLevel).length > 1);
+

[not at google - send to devlin, 2015/03/02 22:22:51]

Actually, one more test:
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/common/exte...
test empty string in webstorePrivate API.

+    chrome.test.succeed();
+  }
+]);