Handle top-level getters and setters in parts.

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

 // Copyright (c) 2016, 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 fasta.source_library_builder;
 
 import 'package:kernel/ast.dart' show
     AsyncMarker,
     ProcedureKind;
 
@@ skipping 265 matching lines @@
         return;
       }
       if (part.partOf != name) {
         print("${part.uri} is part of '${part.partOf}' but is used as a part "
             "by '${name}' ($uri)");
         parts.remove(part);
         return;
       }
     }
     part.members.forEach((String name, Builder builder) {
-      addBuilder(name, builder, -1);
+      if (builder.next != null) {
+        assert(builder.next.next == null);
+        addBuilder(name, builder.next, builder.next.charOffset);
+      }
+      addBuilder(name, builder, builder.charOffset);
     });
     types.addAll(part.types);
     constructorReferences.addAll(part.constructorReferences);
     part.partOfLibrary = this;
     // TODO(ahe): Include metadata from part?
   }
 
   void buildInitialScopes() {
     members.forEach(addToExportScope);
     members.forEach(addToScope);
@@ skipping 136 matching lines @@
   }
 
   /// Called to register [procedure] as a factory whose types are collected in
   /// [factoryDeclaration]. Later, once the class has been built, we can
   /// synthesize type variables on the factory matching the class'.
   void addFactoryDeclaration(
       ProcedureBuilder procedure, DeclarationBuilder<T> factoryDeclaration) {
     factoryDeclarations[procedure] = factoryDeclaration;
   }
 }