Fix bugs and add instrumentation

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 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/dart/analysis/byte_store.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart'
     show AnalysisDriverScheduler, PerformanceLog;
 import 'package:analyzer/src/dart/analysis/file_byte_store.dart';
 import 'package:analyzer/src/dart/analysis/file_state.dart';
@@ skipping 310 matching lines @@
     throw new RequestFailure(
         new RequestError(RequestErrorCode.INVALID_PARAMETER, message));
   }
 
   /**
    * Compute the response that should be returned for the given [request], or
    * `null` if the response has already been sent.
    */
   Response _getResponse(Request request) {
     ResponseResult result = null;
-    switch (request.id) {
+    switch (request.method) {
       case ANALYSIS_REQUEST_HANDLE_WATCH_EVENTS:
         result = handleAnalysisHandleWatchEvents(request.params);
         break;
       case ANALYSIS_REQUEST_REANALYZE:
         result = handleAnalysisReanalyze(request.params);
         break;
       case ANALYSIS_REQUEST_SET_CONTEXT_BUILDER_OPTIONS:
         result = handleAnalysisSetContextBuilderOptions(request.params);
         break;
       case ANALYSIS_REQUEST_SET_CONTEXT_ROOTS:
@@ skipping 54 matching lines @@
       response = new Response(id,
           error: new RequestError(
               RequestErrorCode.PLUGIN_ERROR, exception.toString(),
               stackTrace: stackTrace.toString()));
     }
     if (response != null) {
       _channel.sendResponse(response);
     }
   }
 }