cleanup dart code completion contributors

pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart

Index: pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart
diff --git a/pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart b/pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart
index 89dd436d8a273de5b31f4eba51a8b1f4e0506aad..accbe7d853a980e22e10b699087d447694e8917d 100644
--- a/pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart
+++ b/pkg/analysis_server/lib/src/services/completion/dart/imported_reference_contributor.dart
@@ -48,22 +48,11 @@ class ImportedReferenceContributor extends DartCompletionContributor {
       return EMPTY_LIST;
     }
 
-    List<ImportElement> imports = await request.resolveImports();
+    List<ImportElement> imports = request.libraryElement.imports;
     if (imports == null) {
       return EMPTY_LIST;
     }
 
-    // If the target is in an expression
-    // then resolve the outermost/entire expression
-    AstNode node = request.target.containingNode;
-    if (node is Expression) {
-      await request.resolveContainingExpression(node);
-
-      // Discard any cached target information
-      // because it may have changed as a result of the resolution
-      node = request.target.containingNode;
-    }
-
     this.request = request;
     this.optype = (request as DartCompletionRequestImpl).opType;
     List<CompletionSuggestion> suggestions = <CompletionSuggestion>[];