Add a "librarySource" field to CompilationUnitElementImpl.

pkg/analyzer/test/generated/element_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.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.element_test;
 
 import 'package:analyzer/src/generated/ast.dart';
@@ skipping 3545 matching lines @@
       expect(prefixes[0], same(prefixB));
       expect(prefixes[1], same(prefixA));
     }
   }
 
   void test_getUnits() {
     AnalysisContext context = createAnalysisContext();
     LibraryElementImpl library = ElementFactory.library(context, "test");
     CompilationUnitElement unitLib = library.definingCompilationUnit;
     CompilationUnitElementImpl unitA =
-        ElementFactory.compilationUnit("unit_a.dart");
+        ElementFactory.compilationUnit("unit_a.dart", unitLib.source);
     CompilationUnitElementImpl unitB =
-        ElementFactory.compilationUnit("unit_b.dart");
+        ElementFactory.compilationUnit("unit_b.dart", unitLib.source);
     library.parts = <CompilationUnitElement>[unitA, unitB];
     expect(library.units,
         unorderedEquals(<CompilationUnitElement>[unitLib, unitA, unitB]));
   }
 
   void test_getVisibleLibraries_cycle() {
     AnalysisContext context = createAnalysisContext();
     LibraryElementImpl library = ElementFactory.library(context, "app");
     LibraryElementImpl libraryA = ElementFactory.library(context, "A");
     libraryA.imports =
@@ skipping 381 matching lines @@
 }
 
 class _FunctionTypeImplTest_isSubtypeOf_baseCase_classFunction
     extends InterfaceTypeImpl {
   _FunctionTypeImplTest_isSubtypeOf_baseCase_classFunction(ClassElement arg0)
       : super.con1(arg0);
 
   @override
   bool get isDartCoreFunction => true;
 }