Remove uses of the old plugin model from the analysis server

pkg/analysis_server/lib/src/socket_server.dart

Index: pkg/analysis_server/lib/src/socket_server.dart
diff --git a/pkg/analysis_server/lib/src/socket_server.dart b/pkg/analysis_server/lib/src/socket_server.dart
index 5295b24cbbbf0a176e77d9ca98f58e5595fcbc61..f766bab24524ca97c96bca7986fbd48f67d1696a 100644
--- a/pkg/analysis_server/lib/src/socket_server.dart
+++ b/pkg/analysis_server/lib/src/socket_server.dart
@@ -6,7 +6,6 @@ import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/channel/channel.dart';
-import 'package:analysis_server/src/plugin/server_plugin.dart';
 import 'package:analysis_server/src/server/diagnostic_server.dart';
 import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
@@ -32,7 +31,6 @@ class SocketServer {
   final DartSdk defaultSdk;
   final InstrumentationService instrumentationService;
   final DiagnosticServer diagnosticServer;
-  final ServerPlugin serverPlugin;
   final ResolverProvider fileResolverProvider;
   final ResolverProvider packageResolverProvider;
 
@@ -53,7 +51,6 @@ class SocketServer {
       this.defaultSdk,
       this.instrumentationService,
       this.diagnosticServer,
-      this.serverPlugin,
       this.fileResolverProvider,
       this.packageResolverProvider);
 
@@ -87,7 +84,6 @@ class SocketServer {
         serverChannel,
         resourceProvider,
         new PubPackageMapProvider(resourceProvider, defaultSdk),
-        serverPlugin,
         analysisServerOptions,
         sdkManager,
         instrumentationService,