Prepare for decoupling analyzer ASTs from element model.

pkg/analyzer/test/src/context/context_test.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 analyzer.test.src.context.context_test;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/resolution_accessors.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/dart/element/visitor.dart';
 import 'package:analyzer/error/error.dart';
 import 'package:analyzer/exception/exception.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/source/package_map_resolver.dart';
 import 'package:analyzer/src/cancelable_future.dart';
 import 'package:analyzer/src/context/cache.dart';
@@ skipping 2592 matching lines @@
     comparer.expectNoDifferences();
   }
 
   void test_resolveCompilationUnit_import_relative() {
     Source sourceA =
         addSource("/libA.dart", "library libA; import 'libB.dart'; class A{}");
     addSource("/libB.dart", "library libB; class B{}");
     CompilationUnit compilationUnit =
         context.resolveCompilationUnit2(sourceA, sourceA);
     expect(compilationUnit, isNotNull);
-    LibraryElement library = compilationUnit.element.library;
+    LibraryElement library = elementForCompilationUnit(compilationUnit).library;
     List<LibraryElement> importedLibraries = library.importedLibraries;
     assertNamedElements(importedLibraries, ["dart.core", "libB"]);
   }
 
   void test_resolveCompilationUnit_import_relative_cyclic() {
     Source sourceA =
         addSource("/libA.dart", "library libA; import 'libB.dart'; class A{}");
     addSource("/libB.dart", "library libB; import 'libA.dart'; class B{}");
     CompilationUnit compilationUnit =
         context.resolveCompilationUnit2(sourceA, sourceA);
     expect(compilationUnit, isNotNull);
-    LibraryElement library = compilationUnit.element.library;
+    LibraryElement library = elementForCompilationUnit(compilationUnit).library;
     List<LibraryElement> importedLibraries = library.importedLibraries;
     assertNamedElements(importedLibraries, ["dart.core", "libB"]);
   }
 
   void test_resolveCompilationUnit_library() {
     Source source = addSource("/lib.dart", "library lib;");
     LibraryElement library = context.computeLibraryElement(source);
     CompilationUnit compilationUnit =
         context.resolveCompilationUnit(source, library);
     expect(compilationUnit, isNotNull);
@@ skipping 1846 matching lines @@
         r'''
 import 'a.dart';
 main() {
   new A();
 }
 ''');
     _performPendingAnalysisTasks();
     expect(context.getErrors(a).errors, hasLength(0));
     expect(context.getErrors(b).errors, hasLength(0));
     var unitA = context.getResolvedCompilationUnit2(a, a);
-    var unitElementA = unitA.element;
+    var unitElementA = elementForCompilationUnit(unitA);
     var libraryElementA = unitElementA.library;
     // Update a.dart, no declaration changes.
     context.setContents(
         a,
         r'''
 class A {
   A();
 }
 class B {
   B();
@@ skipping 923 matching lines @@
    * Initialize the visitor.
    */
   _ElementGatherer();
 
   @override
   void visitElement(Element element) {
     elements[element] = element;
     super.visitElement(element);
   }
 }