dart2js: Run prepareNativeClasses in the program builder.

pkg/compiler/lib/src/js_emitter/model.dart

Index: pkg/compiler/lib/src/js_emitter/model.dart
diff --git a/pkg/compiler/lib/src/js_emitter/model.dart b/pkg/compiler/lib/src/js_emitter/model.dart
index 7d011ada585a4a6be4e714aceded5d92d40b2034..5d36b36458299492ea9400ea9b3c2bbd133942f0 100644
--- a/pkg/compiler/lib/src/js_emitter/model.dart
+++ b/pkg/compiler/lib/src/js_emitter/model.dart
@@ -15,13 +15,22 @@ class Program {
   final List<Fragment> fragments;
   final List<Class> nativeClasses;
   final bool outputContainsConstantList;
+  final bool outputContainsNativeClasses;
   /// A map from load id to the list of fragments that need to be loaded.
   final Map<String, List<Fragment>> loadMap;
 
+  /// Additional properties that have to be added to classes.
+  final Map<Class, Map<String, js.Expression>> additionalProperties;
+
   Program(this.fragments,
           this.nativeClasses,
-          this.outputContainsConstantList,
-          this.loadMap);
+          this.additionalProperties,
+          this.loadMap,
+          {this.outputContainsNativeClasses,

[herhut, 2015/01/26 13:50:14]

I am not very keen on this pattern. I assume this is supposed to increase
readability at call sites and I buy that. However, in non-checked mode, this
will fail with strange errors (as null gets propagated). 

[floitsch, 2015/01/26 17:50:40]

I don't think I agree.
Devs should run their code in checked mode at least once. If I add a new call to
this function and I forget an argument it should be detected at first run.
I furthermore believe that the code is read more frequently than it is written.
(In particular calls to this constructor).

+           this.outputContainsConstantList}) {
+    assert(outputContainsNativeClasses != null);
+    assert(outputContainsConstantList != null);
+  }
 
   bool get isSplit => fragments.length > 1;
   Iterable<Fragment> get deferredFragments => fragments.skip(1);