dart2js: use WorldImpact for dump_info

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 2fef15ca51747063da26d524ccd0679786aa8824..5a085e375f4aa43886a3d46ec7b31fa92aeb6d53 100644
--- a/pkg/compiler/lib/src/enqueue.dart
+++ b/pkg/compiler/lib/src/enqueue.dart
@@ -888,8 +888,8 @@ class ResolutionEnqueuer extends Enqueuer {
 /// [Enqueuer] which is specific to code generation.
 class CodegenEnqueuer extends Enqueuer {
   final Queue<CodegenWorkItem> queue;
-  final Map<Element, js.Expression> generatedCode =
-      new Map<Element, js.Expression>();
+  final Map<Element, js.Expression> generatedCode = <Element, js.Expression>{};
+  final Map<Element, WorldImpact> impacts = <Element, WorldImpact>{};

[Siggi Cherem (dart-lang), 2015/11/12 01:10:59]

since this is only used by dump-info, how about storing this directly in the
dumpinfo task, and only set it conditionally when dump info is enabled (that way
we save the space when it is not)

[Harry Terkelsen, 2015/11/12 01:25:40]

Johnni and I talked about this today. Johnni is working on a more general
solution to the problem of whether or not to cache WorldImpacts based on if we
need it for dump-info or for deferred-load. The 'impacts' cache should be
temporary, but I'll move it to the dump info task anyways since it's a quick and
harmless change.

 
   final Set<Element> newlyEnqueuedElements;