Run dart2js tests unmodified in browser.

dart/lib/compiler/implementation/js_backend/emitter.dart

Index: dart/lib/compiler/implementation/js_backend/emitter.dart
diff --git a/dart/lib/compiler/implementation/js_backend/emitter.dart b/dart/lib/compiler/implementation/js_backend/emitter.dart
index f63d93fe81bac85692c270522be4a6cba4c5c4bb..132d3e973784202d930c63deff65493a88d7c6d7 100644
--- a/dart/lib/compiler/implementation/js_backend/emitter.dart
+++ b/dart/lib/compiler/implementation/js_backend/emitter.dart
@@ -1215,7 +1215,9 @@ $mainEnsureGetter
       mainCall = '${namer.isolateAccess(main)}()';
     }
     buffer.add("""
-if (typeof document != 'undefined' && document.readyState != 'complete') {
+if (typeof dartMainRunner == 'function') {

[kasperl, 2012/09/06 10:29:29]

Somehow it feels shaky to not wait until the document has loaded if the
dartMainRunner hook has been set. Would it be possible to simply wrap the
mainCall in dartMainRunner if it is set instead but keep the document.readyState
logic?

[ahe, 2012/09/08 13:32:32]

Done.

+  dartMainRunner(function() { ${mainCall}; });
+} else if (typeof document != 'undefined' && document.readyState != 'complete') {
   document.addEventListener('readystatechange', function () {
     if (document.readyState == 'complete') {
       ${mainCall};