Get rid of global Gerrit Api methods

Change-Id: I240680b46956e5d50eaf3857b14e331596c44e01
diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.html b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.html
index 3288fb0..36b0caa 100644
--- a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.html
+++ b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_test.html
@@ -35,6 +35,10 @@
 import '../../core/gr-router/gr-router.js';
 import './gr-change-metadata.js';
 import {GerritNav} from '../../core/gr-navigation/gr-navigation.js';
+import {pluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader.js';
+import {initGerritPluginApi} from '../../shared/gr-js-api-interface/gr-gerrit.js';
+
+initGerritPluginApi();
 
 suite('gr-change-metadata tests', () => {
   let element;
@@ -758,7 +762,7 @@
           },
           '0.1',
           'http://some/plugins/url.html');
-      Gerrit._loadPlugins([]);
+      pluginLoader.loadPlugins([]);
       flush(() => {
         assert.strictEqual(hookEl.plugin, plugin);
         assert.strictEqual(hookEl.change, element.change);