Frog now knows about the JS global object, and prevents name collisions with user code.

frog/type.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class Type extends Element {
   bool isTested = false;
   bool isChecked = false;
 
   /**
    * For core types (int, String, etc) this is the generated type assertion
@@ skipping 58 matching lines @@
   /** Gets the :call method for a function type. */
   MethodMember getCallMethod() => null;
 
   /** These types may not be implemented or extended by user code. */
   bool get isClosed() => isString || isBool || isNum || isFunction || isVar;
 
   bool get isUsed() => false;
 
   bool get isGeneric() => false;
 
-  bool get isHiddenNativeType() => false;
+  NativeType get nativeType() => null;
+  bool get isHiddenNativeType() =>
+      (nativeType != null && nativeType.isConstructorHidden);
+  bool get isJsGlobalObject() =>
+      (nativeType != null && nativeType.isJsGlobalObject);
 
   bool get hasTypeParams() => false;
 
   String get typeofName() => null;
 
   Map<String, Member> get members() => null;
   Definition get definition() => null;
   FactoryMap get factories() => null;
 
   // TODO(jmesserly): should try using a const list instead of null to represent
@@ skipping 634 matching lines @@
     setDefinition(definition);
   }
 
   void setDefinition(Definition def) {
     assert(definition == null);
     definition = def;
     if (definition is TypeDefinition && definition.nativeType != null) {
       isNative = true;
     }
     if (definition != null && definition.typeParameters != null) {