Settings Router Refactor: Update subpage-back button to use history back sometimes.

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

Index: chrome/test/data/webui/settings/cr_settings_browsertest.js
diff --git a/chrome/test/data/webui/settings/cr_settings_browsertest.js b/chrome/test/data/webui/settings/cr_settings_browsertest.js
index 1dd36378ea1af0f607579e598d0f957f8089e2d5..7b8dd08a4ccd8dc2830a77eae728f92843974cf1 100644
--- a/chrome/test/data/webui/settings/cr_settings_browsertest.js
+++ b/chrome/test/data/webui/settings/cr_settings_browsertest.js
@@ -558,24 +558,14 @@ CrSettingsSubpageTest.prototype = {
 
   /** @override */
   browsePreload: 'chrome://md-settings/settings_page/settings_subpage.html',
+
+  extraLibraries: CrSettingsBrowserTest.prototype.extraLibraries.concat([
+    'settings_subpage_test.js',
+  ]),
 };
 
 TEST_F('CrSettingsSubpageTest', 'SettingsSubpage', function() {
-  suite('SettingsSubpage', function() {
-    test('can navigate to parent', function() {
-      PolymerTest.clearBody();
-
-      settings.navigateTo(settings.Route.SYNC);
-      assertEquals(settings.Route.SYNC, settings.getCurrentRoute());
-
-      var subpage = document.createElement('settings-subpage');
-      document.body.appendChild(subpage);
-
-      MockInteractions.tap(subpage.$$('paper-icon-button'));
-      assertEquals(settings.Route.PEOPLE, settings.getCurrentRoute());
-    });
-  });
-
+  settings_subpage.registerTests();
   mocha.run();
 });