Only add JS once, and not to very single patched library.

lib/compiler/implementation/native_handler.dart

Index: lib/compiler/implementation/native_handler.dart
diff --git a/lib/compiler/implementation/native_handler.dart b/lib/compiler/implementation/native_handler.dart
index c11bafdccc2bac72ee4c3779909a33df45506f2c..d4cb78e070bcc081328a30883fe1072ff22dbe02 100644
--- a/lib/compiler/implementation/native_handler.dart
+++ b/lib/compiler/implementation/native_handler.dart
@@ -83,7 +83,7 @@ void maybeEnableNative(Compiler compiler,
       || libraryName == 'dart:isolate'
       || libraryName == 'dart:html') {
     library.canUseNative = true;
-    library.addToScope(compiler.findHelper(const SourceString('JS')), compiler);
+    compiler.addForeignFunctions(library);

[ahe, 2012/08/21 11:28:31]

I'm not sure about this. What do you need?

[Anders Johnsen, 2012/08/21 11:40:23]

The problem is not here, but in the other file. We add JS scope to every library
that is being patches. This was okay before the latest changes, but the library
and the patch library is one and same library. This means that if we patch
isolate, we'll end up adding JS twice. My argument is that we should only add JS
(and the other helper methods in ForeignFunctions) here, and _only_ here.

[ahe, 2012/08/21 12:01:16]

I don't think the patch libraries need all the foreign functions. Some of them
are pretty powerful and should only be used in our interceptors.

If you're unifying dart:isolate, then I don't think you should need to enable
native at all for the isolate library.

[Anders Johnsen, 2012/08/21 14:31:11]

Thank you for explaining, I've reverted this particular change. I agree, don't
expose more then needed!

     if (compiler.jsIndexingBehaviorInterface !== null) {
       library.addToScope(compiler.jsIndexingBehaviorInterface, compiler);
     }