Implement library access restrictions and privacy.

pkg/front_end/lib/src/fasta/source/source_library_builder.dart

Index: pkg/front_end/lib/src/fasta/source/source_library_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/source/source_library_builder.dart b/pkg/front_end/lib/src/fasta/source/source_library_builder.dart
index 49daa15ba073d377ecb56bb63e0ab783c3d6ab19..31b508b011350579af4c38c9214e85e9f11c7b5e 100644
--- a/pkg/front_end/lib/src/fasta/source/source_library_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_library_builder.dart
@@ -161,8 +161,8 @@ abstract class SourceLibraryBuilder<T extends TypeBuilder, R>
         newFileUri = fileUri.resolve(path);
       }
     }
-    parts
-        .add(loader.read(resolvedUri, -1, fileUri: newFileUri, accessor: this));
+    parts.add(loader.read(resolvedUri, charOffset,
+        fileUri: newFileUri, accessor: this));
   }
 
   void addPartOf(List<MetadataBuilder> metadata, String name, String uri) {