Issue 20827. Add imports as needed the 'Add type annotation' Quick Assist.

pkg/analysis_server/lib/src/services/refactoring/extract_method.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library services.src.refactoring.extract_method;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/name_suggestion.dart';
@@ skipping 287 matching lines @@
         // closure
         if (_selectionFunctionExpression != null) {
           declarationSource = '${name}${returnExpressionSource}';
           if (_selectionFunctionExpression.body is ExpressionFunctionBody) {
             declarationSource += ';';
           }
         }
         // expression
         if (_selectionExpression != null) {
           // add return type
+          Set<LibraryElement> librariesToImport = new Set<LibraryElement>();
+          // TODO(scheglov) use librariesToImport
           String returnTypeName =
-              utils.getExpressionTypeSource(_selectionExpression);
+              utils.getExpressionTypeSource(_selectionExpression, librariesToImport);
           if (returnTypeName != null && returnTypeName != 'dynamic') {
             annotations += '${returnTypeName} ';
           }
           // just return expression
           declarationSource =
               '${annotations}${signature} => ${returnExpressionSource};';
         }
         // statements
         if (_selectionStatements != null) {
           if (returnType.isNotEmpty) {
@@ skipping 291 matching lines @@
               sb.toString().trim()));
     }
     // done
     return result;
   }
 
   void _initializeReturnType() {
     if (_returnType == null) {
       returnType = 'void';
     } else {
-      returnType = utils.getTypeSource(_returnType);
+      Set<LibraryElement> librariesToImport = new Set<LibraryElement>();
+      // TODO(scheglov) use librariesToImport
+      returnType = utils.getTypeSource(_returnType, librariesToImport);
     }
     if (returnType == 'dynamic') {
       returnType = '';
     }
   }
 
   /**
    * Checks if the given [VariableElement] is declared in [selectionRange].
    */
   bool _isDeclaredInSelection(VariableElement element) {
@@ skipping 300 matching lines @@
     }
     // prepare normalized node source
     _SourcePattern nodePattern = ref._getSourcePattern(nodeRange);
     String nodeSource = _getNormalizedSource(nodePattern.patternSource);
     // if matches normalized node source, then add as occurrence
     if (nodeSource == selectionSource) {
       _Occurrence occurrence =
           new _Occurrence(nodeRange, ref.selectionRange.intersects(nodeRange));
       ref._occurrences.add(occurrence);
       // prepare mapping of parameter names to the occurrence variables
-      nodePattern.originalToPatternNames.forEach((String originalName, String patternName) {
+      nodePattern.originalToPatternNames.forEach(
+          (String originalName, String patternName) {
         String selectionName = patternToSelectionName[patternName];
         occurrence._parameterOldToOccurrenceName[selectionName] = originalName;
       });
       // update static
       if (forceStatic) {
         ref._staticContext = true;
       }
       // we have match
       return true;
     }
@@ skipping 39 matching lines @@
           return null;
         }
         // if declared outside, add parameter
         if (!ref._isDeclaredInSelection(variableElement)) {
           String variableName = variableElement.displayName;
           // add parameter
           RefactoringMethodParameter parameter =
               ref._parametersMap[variableName];
           if (parameter == null) {
             DartType parameterType = node.bestType;
-            String parameterTypeName = ref.utils.getTypeSource(parameterType);
+            Set<LibraryElement> librariesToImport = new Set<LibraryElement>();
+            // TODO(scheglov) use librariesToImport
+            String parameterTypeName =
+                ref.utils.getTypeSource(parameterType, librariesToImport);
             parameter = new RefactoringMethodParameter(
                 RefactoringMethodParameterKind.REQUIRED,
                 parameterTypeName,
                 variableName,
                 id: variableName);
             ref._parameters.add(parameter);
             ref._parametersMap[variableName] = parameter;
           }
           // add reference to parameter
           ref._addParameterReference(variableName, nodeRange);
@@ skipping 82 matching lines @@
 
 /**
  * Generalized version of some source, in which references to the specific
  * variables are replaced with pattern variables, with back mapping from the
  * pattern to the original variable names.
  */
 class _SourcePattern {
   String patternSource;
   Map<String, String> originalToPatternNames = {};
 }