Add line starts into unlinked units.

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

Index: pkg/analyzer/test/src/summary/summary_common.dart
diff --git a/pkg/analyzer/test/src/summary/summary_common.dart b/pkg/analyzer/test/src/summary/summary_common.dart
index d3e94d34b9d12b3deb0c00839e69f165275d3629..d5f2876096b223e4295a130517c2a6e2f00fd568 100644
--- a/pkg/analyzer/test/src/summary/summary_common.dart
+++ b/pkg/analyzer/test/src/summary/summary_common.dart
@@ -8659,6 +8659,17 @@ library foo;''';
         expectedTargetUnit: 2);
   }
 
+  test_lineStarts() {
+    String text = '''
+int foo;
+class Test {}
+
+int bar;'''
+        .replaceAll('\r\n', '\n');
+    serializeLibraryText(text);
+    expect(unlinkedUnits[0].lineStarts, [0, 9, 23, 24]);
+  }
+
   test_linked_reference_reuse() {
     if (skipFullyLinkedData) {
       return;