Prepare for decoupling analyzer ASTs from element model.

pkg/analysis_server/lib/src/computer/computer_highlights2.dart

Index: pkg/analysis_server/lib/src/computer/computer_highlights2.dart
diff --git a/pkg/analysis_server/lib/src/computer/computer_highlights2.dart b/pkg/analysis_server/lib/src/computer/computer_highlights2.dart
index 7d67c261e07f292f47c9fb1c5458b76ff9e39d0b..bc8486bad568ec0045da8bea4510707a8898f265 100644
--- a/pkg/analysis_server/lib/src/computer/computer_highlights2.dart
+++ b/pkg/analysis_server/lib/src/computer/computer_highlights2.dart
@@ -6,6 +6,7 @@ library computer.highlights2;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart' hide Element;
 import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/resolution_accessors.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ -428,7 +429,7 @@ class DartUnitHighlightsComputer2 {
     if (e is SimpleIdentifier && e.staticElement is PrefixElement) {
       return false;
     }
-    return e.bestType.isDynamic;
+    return bestTypeForExpression(e).isDynamic;
   }
 }