frog isolate fixes: minor changes to the isolate library + architecture.py

frog/world.dart

Index: frog/world.dart
diff --git a/frog/world.dart b/frog/world.dart
index 9b6bcfe43307d8c66b52c31db3670434b3c430a5..7f4b2e44707b8ff2b4cd6695cd9f3babc6413e58 100644
--- a/frog/world.dart
+++ b/frog/world.dart
@@ -215,9 +215,11 @@ class World {
       } else if (namedPri > existingPri) {
         // New one takes priority over existing
         _renameJavascriptTopName(existing);
-      } else {
+      } else if ((!_isDomWorker(named) || !_isIsolateWorker(existing))
+          && (!_isDomWorker(existing) || !_isIsolateWorker(named))) {
         // Two conflicting native names or names in corelib. Libraries need
-        // to be fixed.
+        // to be fixed. We exclude the case when isolate defines Worker, so that
+        // corelib doesn't depend on the dom lib.
         world.internalError('conflicting JS name "$name" of same '
             + 'priority $existingPri: (already defined in) '
             + '${existing.span.locationText} with priority $namedPri)',
@@ -229,6 +231,16 @@ class World {
     }
   }
 
+  /** Whether element is the dom definition of Worker. */
+  _isDomWorker(Element e) {
+    return e.library == dom && e.nativeName == 'Worker';
+  }
+
+  /** Whether element is the isolate (corelib) definition of Worker. */
+  _isIsolateWorker(Element e) {
+    return e.library == coreimpl && e.nativeName == 'Worker';
+  }
+
   /** Renames an [Element] that had a name conflict in the generated JS. */
   _renameJavascriptTopName(Element named) {
     named._jsname = '${named.library.jsname}_${named.jsname}';