dart2js: report output unit imports to dump-info

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 f9faa1a99a936a17a8170963bb6375096d014ee6..09ab8e58963af245e88d46fe9d4a0bf6359aad5f 100644
--- a/pkg/compiler/lib/src/dump_info.dart
+++ b/pkg/compiler/lib/src/dump_info.dart
@@ -326,6 +326,8 @@ class ElementInfoCollector extends BaseElementVisitor<Info, dynamic> {
       full.Emitter emitter = backend.emitter.emitter;
       OutputUnitInfo info = new OutputUnitInfo(
           outputUnit.name, emitter.outputBuffers[outputUnit].length);
+      info.imports.addAll(outputUnit.imports
+          .map((d) => compiler.deferredLoadTask.importDeferName[d]));
       result.outputUnits.add(info);
       return info;
     });