Don't try to load unnecessary transformers when precompiling executables.

sdk/lib/_internal/pub/lib/src/barback/load_all_transformers.dart

Index: sdk/lib/_internal/pub/lib/src/barback/load_all_transformers.dart
diff --git a/sdk/lib/_internal/pub/lib/src/barback/load_all_transformers.dart b/sdk/lib/_internal/pub/lib/src/barback/load_all_transformers.dart
index 18bf853d4262d8f5e6644cfd32df034ab2f914b1..0420af34cb0e6aced4e7d699ab9096e7a91858e0 100644
--- a/sdk/lib/_internal/pub/lib/src/barback/load_all_transformers.dart
+++ b/sdk/lib/_internal/pub/lib/src/barback/load_all_transformers.dart
@@ -32,7 +32,8 @@ import 'transformers_needed_by_transformers.dart';
 Future loadAllTransformers(AssetEnvironment environment,
     BarbackServer transformerServer) {
   var transformersNeededByTransformers =
-      computeTransformersNeededByTransformers(environment.graph);
+      computeTransformersNeededByTransformers(environment.graph,
+          packages: environment.packages);

[Bob Nystrom, 2014/09/12 17:57:50]

Is this needed? Won't packages: default to this if omitted?

[nweiz, 2014/09/15 23:17:35]

No, it will default to [environment.graph.packages.keys], which includes
packages that don't need to be loaded.

 
   var buffer = new StringBuffer();
   buffer.writeln("Transformer dependencies:");