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

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

Index: chrome/test/data/webui/settings/privacy_page_test.js
diff --git a/chrome/test/data/webui/settings/privacy_page_test.js b/chrome/test/data/webui/settings/privacy_page_test.js
index 4bc41793f60f461211bb4401adead7c494d49522..647c8ace6503dc119da7751e27b125d08fa5ca62 100644
--- a/chrome/test/data/webui/settings/privacy_page_test.js
+++ b/chrome/test/data/webui/settings/privacy_page_test.js
@@ -70,6 +70,10 @@ cr.define('settings_privacy_page', function() {
       /** @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;