xpack_main legacy plugin pre-removal cleanup (#76257)

* cleanup xpack_main legacy plugin, remove capabilities mixin

* fix test env

* delete injectXpackSignature and related tests

src/legacy/server/kbn_server.js

@@ -34,7 +34,6 @@ import configCompleteMixin from './config/complete';
 import { optimizeMixin } from '../../optimize';
 import * as Plugins from './plugins';
 import { savedObjectsMixin } from './saved_objects/saved_objects_mixin';
-import { capabilitiesMixin } from './capabilities';
 import { serverExtensionsMixin } from './server_extensions';
 import { uiMixin } from '../ui';
 import { i18nMixin } from './i18n';
@@ -115,9 +114,6 @@ export default class KbnServer {
         // setup saved object routes
         savedObjectsMixin,
 
-        // setup capabilities routes
-        capabilitiesMixin,
-
         // setup routes that serve the @kbn/optimizer output
         optimizeMixin,
 

x-pack/legacy/plugins/xpack_main/index.js

@@ -6,12 +6,9 @@
 
 import { resolve } from 'path';
 import { mirrorPluginStatus } from '../../server/lib/mirror_plugin_status';
-import { replaceInjectedVars } from './server/lib/replace_injected_vars';
 import { setupXPackMain } from './server/lib/setup_xpack_main';
 import { xpackInfoRoute, settingsRoute } from './server/routes/api/v1';
 
-export { callClusterFactory } from './server/lib/call_cluster_factory';
-
 export const xpackMain = (kibana) => {
   return new kibana.Plugin({
     id: 'xpack_main',
@@ -25,32 +22,7 @@ export const xpackMain = (kibana) => {
       }).default();
     },
 
-    uiCapabilities(server) {
-      const featuresPlugin = server.newPlatform.setup.plugins.features;
-      if (!featuresPlugin) {
-        throw new Error('New Platform XPack Features plugin is not available.');
-      }
-      return featuresPlugin.getFeaturesUICapabilities();
-    },
-
-    uiExports: {
-      replaceInjectedVars,
-      injectDefaultVars(server) {
-        const config = server.config();
-
-        return {
-          activeSpace: null,
-          spacesEnabled: config.get('xpack.spaces.enabled'),
-        };
-      },
-    },
-
     init(server) {
-      const featuresPlugin = server.newPlatform.setup.plugins.features;
-      if (!featuresPlugin) {
-        throw new Error('New Platform XPack Features plugin is not available.');
-      }
-
       mirrorPluginStatus(server.plugins.elasticsearch, this, 'yellow', 'red');
 
       setupXPackMain(server);