MD Settings: make chrome://[md-]settings/clearBrowserData URL work

chrome/test/data/webui/settings/privacy_page_test.js

 // Copyright 2016 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.
 
 cr.define('settings_privacy_page', function() {
   /**
    * @constructor
    * @extends {TestBrowserProxy}
    * @implements {settings.PrivacyPageBrowserProxy}
    */
@@ skipping 52 matching lines @@
   };
 
   function registerNativeCertificateManagerTests() {
     suite('NativeCertificateManager', function() {
       /** @type {settings.TestPrivacyPageBrowserProxy} */
       var testBrowserProxy;
 
       /** @type {SettingsPrivacyPageElement} */
       var page;
 
+      suiteSetup(function() {
+        settings.main.rendered = Promise.resolve();

[michaelpg, 2016/06/29 22:46:52]

it's a little unfortunate that our test has to permanently change global state,
just because <settings-main> might not exist. I don't have a better idea though,
at least not without adding more abstraction (PromiseResolverManager?)

[Dan Beam, 2016/06/29 23:12:24]

Agreed. I'll think about this more. We use a lot of browser proxies as ways to
scope globals to a class... but this isn't really being proxied to a browser.
That's why I pushed for a more generic "Delegate" style which is just an
@interface that doesn't require a specific purpose but is injected or set on a
class in production/testing differently (easier to double).

this is one I snuck in before we centered on "browser proxies"
https://cs.chromium.org/search/?q=directiondelegate&sq=package:chromium&type=cs

+      });
+
       setup(function() {
         testBrowserProxy = new TestPrivacyPageBrowserProxy();
         settings.PrivacyPageBrowserProxyImpl.instance_ = testBrowserProxy;
         PolymerTest.clearBody();
         page = document.createElement('settings-privacy-page');
         document.body.appendChild(page);
       });
 
       teardown(function() { page.remove(); });
 
@@ skipping 97 matching lines @@
 
   return {
     registerTests: function() {
       if (cr.isMac || cr.isWin)
         registerNativeCertificateManagerTests();
 
       registerClearBrowsingDataTests();
     },
   };
 });