Some cleanups to Frog to avoid looking up its builtin types too much

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;
   bool isWritten = false;
 
   /**
@@ skipping 89 matching lines @@
   // the absence of type parameters.
   Collection<Type> get typeArgsInOrder() => null;
   DefinedType get genericType() => this;
 
   // TODO(jmesserly): what should these do for ParameterType?
   List<Type> get interfaces() => null;
   Type get parent() => null;
 
   Map<String, Member> getAllMembers() => {};
 
-  /** The native name of this element if it has one. */
-  String get nativeName() => isNative ? definition.nativeType.name : null;
+  /** The native name of this element if it has one, otherwise the JS name. */
+  String get nativeName() => isNative ? definition.nativeType.name : jsname;
 
   /**
    * Avoid the native name if hidden native. It might exist on some browsers and
    * we want to use it if it does.
    */
   bool get avoidNativeName() => isHiddenNativeType;
 
   bool _hasNativeSubtypes;
   bool get hasNativeSubtypes() {
     if (_hasNativeSubtypes == null) {
@@ skipping 1223 matching lines @@
       } else {
         break;
       }
     }
     if (name.startsWith('=')) {
       name = name.substring(1);
       isSingleton = true;
     }
   }
 }