dart2js: dump info about dependencies added by the enqueuer

pkg/compiler/lib/src/enqueue.dart

Index: pkg/compiler/lib/src/enqueue.dart
diff --git a/pkg/compiler/lib/src/enqueue.dart b/pkg/compiler/lib/src/enqueue.dart
index 55deafc40041e37bc820d40482c0e9de2f503e92..f695bceca6151bf1d7a488860ee8713499ee8dfb 100644
--- a/pkg/compiler/lib/src/enqueue.dart
+++ b/pkg/compiler/lib/src/enqueue.dart
@@ -139,7 +139,12 @@ abstract class Enqueuer {
    */
   void addToWorkList(Element element) {
     assert(invariant(element, element.isDeclaration));
-    internalAddToWorkList(element);
+    if (internalAddToWorkList(element) && compiler.dumpInfo) {
+      // TODO(sigmund): add other missing dependencies (internals, selectors
+      // enqueued after allocations), also enable only for the codegen enqueuer.
+      compiler.dumpInfoTask.registerDependency(
+          compiler.currentElement, element);
+    }
   }
 
   /**