Make FixContributor asynchronous.

pkg/analysis_server/lib/src/services/correction/fix.dart

Index: pkg/analysis_server/lib/src/services/correction/fix.dart
diff --git a/pkg/analysis_server/lib/src/services/correction/fix.dart b/pkg/analysis_server/lib/src/services/correction/fix.dart
index 73f9bd5732474c3ba70768484dbbd7da87ed658a..124d0f0832788e527947fd865ee20715b1389fc3 100644
--- a/pkg/analysis_server/lib/src/services/correction/fix.dart
+++ b/pkg/analysis_server/lib/src/services/correction/fix.dart
@@ -4,6 +4,8 @@
 
 library analysis_server.src.services.correction.fix;
 
+import 'dart:async';
+
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
 import 'package:analysis_server/src/plugin/server_plugin.dart';
 import 'package:analyzer/file_system/file_system.dart';
@@ -17,14 +19,17 @@ import 'package:analyzer/src/generated/parser.dart';
  * reported after it's source was analyzed in the given [context]. The [plugin]
  * is used to get the list of fix contributors.
  */
-List<Fix> computeFixes(ServerPlugin plugin, ResourceProvider resourceProvider,
-    AnalysisContext context, AnalysisError error) {
+Future<List<Fix>> computeFixes(
+    ServerPlugin plugin,
+    ResourceProvider resourceProvider,
+    AnalysisContext context,
+    AnalysisError error) async {
   List<Fix> fixes = <Fix>[];
   List<FixContributor> contributors = plugin.fixContributors;
+  FixContext fixContext = new FixContextImpl(resourceProvider, context, error);
   for (FixContributor contributor in contributors) {
     try {
-      List<Fix> contributedFixes =
-          contributor.computeFixes(resourceProvider, context, error);
+      List<Fix> contributedFixes = await contributor.computeFixes(fixContext);
       if (contributedFixes != null) {
         fixes.addAll(contributedFixes);
       }
@@ -202,3 +207,24 @@ class DartFixKind {
   static const USE_NOT_EQ_NULL =
       const FixKind('USE_NOT_EQ_NULL', 50, "Use != null instead of 'is! Null'");
 }
+
+/**
+ * The implementation of [FixContext].
+ */
+class FixContextImpl implements FixContext {
+  @override
+  final ResourceProvider resourceProvider;
+
+  @override
+  final AnalysisContext analysisContext;
+
+  @override
+  final AnalysisError error;
+
+  FixContextImpl(this.resourceProvider, this.analysisContext, this.error);
+
+  FixContextImpl.from(FixContext other)
+      : resourceProvider = other.resourceProvider,
+        analysisContext = other.analysisContext,
+        error = other.error;
+}