Create a public API for contributing fixes and make fixes pluggable

pkg/analysis_server/lib/src/edit/edit_domain.dart

Index: pkg/analysis_server/lib/src/edit/edit_domain.dart
diff --git a/pkg/analysis_server/lib/src/edit/edit_domain.dart b/pkg/analysis_server/lib/src/edit/edit_domain.dart
index 9d4c7df7a57c6cd6dd2faa876219603f7cea982b..4536adbdd7a973936e71287e21d399347e818106 100644
--- a/pkg/analysis_server/lib/src/edit/edit_domain.dart
+++ b/pkg/analysis_server/lib/src/edit/edit_domain.dart
@@ -6,9 +6,11 @@ library edit.domain;
 
 import 'dart:async';
 
+import 'package:analysis_server/edit/fix/fix_core.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/collections.dart';
 import 'package:analysis_server/src/constants.dart';
+import 'package:analysis_server/src/plugin/server_plugin.dart';
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/assist.dart';
 import 'package:analysis_server/src/services/correction/fix.dart';
@@ -40,6 +42,11 @@ class EditDomainHandler implements RequestHandler {
   final AnalysisServer server;
 
   /**
+   * The server plugin that defines the extension points used by this handler.
+   */
+  final ServerPlugin plugin;
+
+  /**
    * The [SearchEngine] for this server.
    */
   SearchEngine searchEngine;
@@ -49,7 +56,7 @@ class EditDomainHandler implements RequestHandler {
   /**
    * Initialize a newly created handler to handle requests for the given [server].
    */
-  EditDomainHandler(this.server) {
+  EditDomainHandler(this.server, this.plugin) {
     searchEngine = server.searchEngine;
     _newRefactoringManager();
   }
@@ -137,7 +144,7 @@ class EditDomainHandler implements RequestHandler {
         for (engine.AnalysisError error in errorInfo.errors) {
           int errorLine = lineInfo.getLocation(error.offset).lineNumber;
           if (errorLine == requestLine) {
-            List<Fix> fixes = computeFixes(unit, error);
+            List<Fix> fixes = computeFixes(plugin, unit.element.context, error);
             if (fixes.isNotEmpty) {
               AnalysisError serverError =
                   newAnalysisError_fromEngine(lineInfo, error);