Add NativeEnqueuer to work with the Enqueuer.

sdk/lib/_internal/compiler/implementation/js_backend/backend.dart

Index: sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
diff --git a/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart b/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
index cf9c8a4ae3c23fc53451f7b1dc623765c7102686..2632ece0e178bd3efac333729d097c518d90a317 100644
--- a/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
+++ b/sdk/lib/_internal/compiler/implementation/js_backend/backend.dart
@@ -811,10 +811,15 @@ class JavaScriptBackend extends Backend {
     invalidateAfterCodegen.clear();
   }
 
-  void processNativeClasses(Enqueuer world,
-                            Collection<LibraryElement> libraries) {
-    native.processNativeClasses(world, emitter, libraries);
-  }
+
+  native.NativeEnqueuer nativeResolutionEnqueuer(Enqueuer world,
+                                                 bool liveTypeAnalysis) =>

[ngeoffray, 2012/11/14 21:17:39]

Use {} instead.

[sra1, 2012/11/15 00:09:10]

OK, but I don't really agree with a style guideline that forces you to change
from => to {} depending on whether you add a parameter or change the name of a
parameter type.
That is causing required edits that the autoindenting in your favorite editor
cannot handle.

It is dangerous to do the change - I forgot 'return' and it cost me some time. 
It is much safer to adopt guidelines that don't force you to make error-prone
changes.

+      new native.NativeResolutionEnqueuer(world, compiler, liveTypeAnalysis);
+
+  native.NativeEnqueuer nativeCodegenEnqueuer(Enqueuer world,
+                                              bool liveTypeAnalysis) =>

[ngeoffray, 2012/11/14 21:17:39]

ditto

+      new native.NativeCodegenEnqueuer(
+          world, compiler, emitter, liveTypeAnalysis);
 
   void assembleProgram() {
     emitter.assembleProgram();