Force Dart unit resolution when elements at offset are requested.

pkg/analysis_server/lib/src/analysis_server.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 analysis.server;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/file_system/file_system.dart';
@@ skipping 773 matching lines @@
     // prepare AnalysisContext
     AnalysisContext context = getAnalysisContext(path);
     if (context == null) {
       return units;
     }
     // add a unit for each unit/library combination
     Source unitSource = getSource(path);
     List<Source> librarySources = context.getLibrariesContaining(unitSource);
     for (Source librarySource in librarySources) {
       CompilationUnit unit =
-          context.getResolvedCompilationUnit2(unitSource, librarySource);
+          context.resolveCompilationUnit2(unitSource, librarySource);
       if (unit != null) {
         units.add(unit);
       }
     }
     // done
     return units;
   }
 
   /**
-   * Returns [AstNode]s at the given [offset] of the given [file].
+   * Returns resolved [AstNode]s at the given [offset] of the given [file].
    *
    * May be empty, but not `null`.
    */
   List<AstNode> getNodesAtOffset(String file, int offset) {
     List<CompilationUnit> units = getResolvedCompilationUnits(file);
     List<AstNode> nodes = <AstNode>[];
     for (CompilationUnit unit in units) {
       AstNode node = new NodeLocator.con1(offset).searchWithin(unit);
       if (node != null) {
         nodes.add(node);
       }
     }
     return nodes;
   }
 
   /**
    * Returns [Element]s at the given [offset] of the given [file].
    *
-   * May be empty if not resolved, but not `null`.
+   * May be empty if cannot be resolved, but not `null`.
    */
   List<Element> getElementsAtOffset(String file, int offset) {
     List<AstNode> nodes = getNodesAtOffset(file, offset);
     return getElementsOfNodes(nodes, offset);
   }
 
   /**
    * Returns [Element]s of the given [nodes].
    *
    * May be empty if not resolved, but not `null`.
@@ skipping 102 matching lines @@
     // send the notification
     channel.sendNotification(
         new ServerErrorParams(
             true,
             exceptionString,
             stackTraceString).toNotification());
   }
 }
 
 typedef void OptionUpdater(AnalysisOptionsImpl options);