Stop using Element.computeNode() in refactorings and fixes.

pkg/analysis_server/lib/src/analysis_server.dart

Index: pkg/analysis_server/lib/src/analysis_server.dart
diff --git a/pkg/analysis_server/lib/src/analysis_server.dart b/pkg/analysis_server/lib/src/analysis_server.dart
index 98e852bff111a9b328728dade7680a9756e32080..4a01b0457bed5d66af1392af08c558e44466696d 100644
--- a/pkg/analysis_server/lib/src/analysis_server.dart
+++ b/pkg/analysis_server/lib/src/analysis_server.dart
@@ -37,12 +37,15 @@ import 'package:analyzer/instrumentation/instrumentation.dart';
 import 'package:analyzer/plugin/resolver_provider.dart';
 import 'package:analyzer/source/pub_package_map_provider.dart';
 import 'package:analyzer/src/context/builder.dart';
+import 'package:analyzer/src/dart/analysis/ast_provider_context.dart';
+import 'package:analyzer/src/dart/analysis/ast_provider_driver.dart';
 import 'package:analyzer/src/dart/analysis/byte_store.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart' as nd;
 import 'package:analyzer/src/dart/analysis/file_byte_store.dart';
 import 'package:analyzer/src/dart/analysis/file_state.dart' as nd;
 import 'package:analyzer/src/dart/analysis/status.dart' as nd;
 import 'package:analyzer/src/dart/ast/utilities.dart';
+import 'package:analyzer/src/dart/element/ast_provider.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer/src/generated/source.dart';
@@ -1115,6 +1118,16 @@ class AnalysisServer {
     channel.sendResponse(response);
   }
 
+  AstProvider getAstProvider(String path) {
+    if (options.enableNewAnalysisDriver) {
+      var analysisDriver = getAnalysisDriver(path);
+      return new AstProviderForDriver(analysisDriver);
+    } else {
+      var analysisContext = getAnalysisContext(path);
+      return new AstProviderForContext(analysisContext);
+    }
+  }
+
   /**
    * Sends a `server.error` notification.
    */