Remove an unused request and the associated type

pkg/analyzer_plugin/lib/plugin/plugin.dart

Index: pkg/analyzer_plugin/lib/plugin/plugin.dart
diff --git a/pkg/analyzer_plugin/lib/plugin/plugin.dart b/pkg/analyzer_plugin/lib/plugin/plugin.dart
index be8f70a5a8d94eb91fe319b2bc0f9e8455075af8..fc9921e18382d7f5f413610d7a522cbd686aef54 100644
--- a/pkg/analyzer_plugin/lib/plugin/plugin.dart
+++ b/pkg/analyzer_plugin/lib/plugin/plugin.dart
@@ -257,14 +257,6 @@ abstract class ServerPlugin {
   }
 
   /**
-   * Handle an 'analysis.setContextBuilderOptions' request.
-   */
-  Future<AnalysisSetContextBuilderOptionsResult>
-      handleAnalysisSetContextBuilderOptions(
-              AnalysisSetContextBuilderOptionsParams parameters) async =>
-          null;
-
-  /**
    * Handle an 'analysis.setContextRoots' request.
    */
   Future<AnalysisSetContextRootsResult> handleAnalysisSetContextRoots(
@@ -508,11 +500,6 @@ abstract class ServerPlugin {
         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);