Update defer loading algorithm:

pkg/compiler/lib/src/dump_info.dart

Index: pkg/compiler/lib/src/dump_info.dart
diff --git a/pkg/compiler/lib/src/dump_info.dart b/pkg/compiler/lib/src/dump_info.dart
index f89bec3c3f0693f593298104b55efdd1fbaa4200..4990b7cccdac4c14971a543c8c0c50abcc4f620f 100644
--- a/pkg/compiler/lib/src/dump_info.dart
+++ b/pkg/compiler/lib/src/dump_info.dart
@@ -349,8 +349,7 @@ class ElementInfoCollector extends BaseElementVisitor<Info, dynamic> {
       assert(outputUnit.name != null || outputUnit.isMainOutput);
       OutputUnitInfo info = new OutputUnitInfo(
           outputUnit.name, backend.emitter.emitter.generatedSize(outputUnit));
-      info.imports.addAll(outputUnit.imports
-          .map((d) => compiler.deferredLoadTask.importDeferName[d]));
+      info.imports.addAll(compiler.deferredLoadTask.getImportNames(outputUnit));
       result.outputUnits.add(info);
       return info;
     });