Replace computeNode() with AstProvider in search.

pkg/analysis_server/lib/src/services/search/search_engine_internal.dart

Index: pkg/analysis_server/lib/src/services/search/search_engine_internal.dart
diff --git a/pkg/analysis_server/lib/src/services/search/search_engine_internal.dart b/pkg/analysis_server/lib/src/services/search/search_engine_internal.dart
index 63a6996d8005ffebaad0e3af360f6ade528d3935..78fbb0f1b4536a5244a4ca35c30b7b8e2c8b0cb7 100644
--- a/pkg/analysis_server/lib/src/services/search/search_engine_internal.dart
+++ b/pkg/analysis_server/lib/src/services/search/search_engine_internal.dart
@@ -13,6 +13,7 @@ import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/visitor.dart';
+import 'package:analyzer/src/dart/element/ast_provider.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/member.dart';
 import 'package:analyzer/src/generated/engine.dart' show AnalysisContext;
@@ -22,12 +23,18 @@ import 'package:analyzer/src/generated/utilities_general.dart';
 import 'package:analyzer/src/summary/idl.dart';
 
 /**
+ * The type of a function that returns the [AstProvider] managing the [file].
+ */
+typedef AstProvider GetAstProvider(String file);

[Brian Wilkerson, 2017/02/03 14:43:47]

Is this necessary? It seems like it's just as performant to create the
AstProvider as it is to create the closure to return the AstProvider, and less
indirection through functions would be better.

[scheglov, 2017/02/03 18:31:36]

AstProvider is bound to a single AnalysisDriver or AnalysisContext.

When we create SearchEngineImpl, we don't know which local Element(s) will be
searched. Depending on the specific element, we need to choose AnalysisDriver,
and so AstProvider.

[Brian Wilkerson, 2017/02/03 18:38:25]

That makes sense. It would be good to add that to a comment so it's clear later.

+
+/**
  * A [SearchEngine] implementation.
  */
 class SearchEngineImpl implements SearchEngine {
   final Index _index;
+  final GetAstProvider _getAstProvider;
 
-  SearchEngineImpl(this._index);
+  SearchEngineImpl(this._index, this._getAstProvider);
 
   @override
   Future<Set<ClassElement>> searchAllSubtypes(ClassElement type) async {
@@ -254,7 +261,8 @@ class SearchEngineImpl implements SearchEngine {
   Future<List<SearchMatch>> _searchReferences_Local(
       Element element, bool isRootNode(AstNode n)) async {
     _LocalReferencesVisitor visitor = new _LocalReferencesVisitor(element);
-    AstNode node = element.computeNode();
+    AstProvider astProvider = _getAstProvider(element.source.fullName);
+    AstNode node = await astProvider.getResolvedNodeForElement(element);
     AstNode enclosingNode = node?.getAncestor(isRootNode);
     enclosingNode?.accept(visitor);
     return visitor.matches;