Remove an unused request and the associated type

pkg/analyzer_plugin/lib/plugin/plugin.dart

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart'
     show AnalysisDriverGeneric, AnalysisDriverScheduler;
@@ skipping 239 matching lines @@
 //      for (String rootPath in rootPaths) {
 //        ContextRoot contextRoot = contextRootContaining(rootPath);
 //        AnalysisDriverGeneric driver = driverMap[contextRoot];
 //        driver.reanalyze(rootPath);
 //      }
       return null;
     }
   }
 
   /**
-   * Handle an 'analysis.setContextBuilderOptions' request.
-   */
-  Future<AnalysisSetContextBuilderOptionsResult>
-      handleAnalysisSetContextBuilderOptions(
-              AnalysisSetContextBuilderOptionsParams parameters) async =>
-          null;
-
-  /**
    * Handle an 'analysis.setContextRoots' request.
    */
   Future<AnalysisSetContextRootsResult> handleAnalysisSetContextRoots(
       AnalysisSetContextRootsParams parameters) async {
     List<ContextRoot> contextRoots = parameters.roots;
     List<ContextRoot> oldRoots = driverMap.keys.toList();
     for (ContextRoot contextRoot in contextRoots) {
       if (!oldRoots.remove(contextRoot)) {
         // The context is new, so we create a driver for it. Creating the driver
         // has the side-effect of adding it to the analysis driver scheduler.
@@ skipping 223 matching lines @@
         result = await handleAnalysisGetNavigation(params);
         break;
       case ANALYSIS_REQUEST_HANDLE_WATCH_EVENTS:
         var params = new AnalysisHandleWatchEventsParams.fromRequest(request);
         result = await handleAnalysisHandleWatchEvents(params);
         break;
       case ANALYSIS_REQUEST_REANALYZE:
         var params = new AnalysisReanalyzeParams.fromRequest(request);
         result = await handleAnalysisReanalyze(params);
         break;
-      case ANALYSIS_REQUEST_SET_CONTEXT_BUILDER_OPTIONS:
-        var params =
-            new AnalysisSetContextBuilderOptionsParams.fromRequest(request);
-        result = await handleAnalysisSetContextBuilderOptions(params);
-        break;
       case ANALYSIS_REQUEST_SET_CONTEXT_ROOTS:
         var params = new AnalysisSetContextRootsParams.fromRequest(request);
         result = await handleAnalysisSetContextRoots(params);
         break;
       case ANALYSIS_REQUEST_SET_PRIORITY_FILES:
         var params = new AnalysisSetPriorityFilesParams.fromRequest(request);
         result = await handleAnalysisSetPriorityFiles(params);
         break;
       case ANALYSIS_REQUEST_SET_SUBSCRIPTIONS:
         var params = new AnalysisSetSubscriptionsParams.fromRequest(request);
@@ skipping 58 matching lines @@
       response = new Response(id, requestTime,
           error: new RequestError(
               RequestErrorCode.PLUGIN_ERROR, exception.toString(),
               stackTrace: stackTrace.toString()));
     }
     if (response != null) {
       _channel.sendResponse(response);
     }
   }
 }