Add line starts into unlinked units.

pkg/analyzer/test/src/summary/summarize_ast_test.dart

Index: pkg/analyzer/test/src/summary/summarize_ast_test.dart
diff --git a/pkg/analyzer/test/src/summary/summarize_ast_test.dart b/pkg/analyzer/test/src/summary/summarize_ast_test.dart
index 0ac50991c8c14ebba767ff5be9dd773276c23724..d6210a69219a10f7236977239bf95e45abd84ad5 100644
--- a/pkg/analyzer/test/src/summary/summarize_ast_test.dart
+++ b/pkg/analyzer/test/src/summary/summarize_ast_test.dart
@@ -10,6 +10,7 @@ import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/src/dart/scanner/reader.dart';
 import 'package:analyzer/src/dart/scanner/scanner.dart';
 import 'package:analyzer/src/generated/error.dart';
+import 'package:analyzer/src/generated/java_engine.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/summary/format.dart';
@@ -332,7 +333,8 @@ abstract class SummaryLinkerTest {
    */
   Source addNamedSource(String filePath, String contents) {
     CompilationUnit unit = _parseText(contents);
-    UnlinkedUnitBuilder unlinkedUnit = serializeAstUnlinked(unit);
+    List<int> lineStarts = StringUtilities.computeLineStarts(contents);
+    UnlinkedUnitBuilder unlinkedUnit = serializeAstUnlinked(unit, lineStarts);
     uriToUnit[absUri(filePath)] = unlinkedUnit;
     // Tests using SummaryLinkerTest don't actually need the returned
     // Source, so we can safely return `null`.
@@ -342,7 +344,9 @@ abstract class SummaryLinkerTest {
   LinkerInputs createLinkerInputs(String text, {String path: '/test.dart'}) {
     Uri testDartUri = Uri.parse(absUri(path));
     CompilationUnit unit = _parseText(text);
-    UnlinkedUnitBuilder unlinkedDefiningUnit = serializeAstUnlinked(unit);
+    List<int> lineStarts = StringUtilities.computeLineStarts(text);
+    UnlinkedUnitBuilder unlinkedDefiningUnit =
+        serializeAstUnlinked(unit, lineStarts);
     uriToUnit[testDartUri.toString()] = unlinkedDefiningUnit;
     LinkerInputs linkerInputs = new LinkerInputs(
         allowMissingFiles,