dart2js: add type arguments to constructor in case the class needs rti.

pkg/compiler/lib/src/js_emitter/class_stub_generator.dart

 // Copyright (c) 2014, 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.
 
 part of dart2js.js_emitter;
 
 class ClassStubGenerator {
   final Namer namer;
   final Compiler compiler;
   final JavaScriptBackend backend;
 
   ClassStubGenerator(this.compiler, this.namer, this.backend);
 
   jsAst.Expression generateClassConstructor(ClassElement classElement,
                                             Iterable<String> fields) {
     // TODO(sra): Implement placeholders in VariableDeclaration position:
     //
     //     String constructorName = namer.getNameOfClass(classElement);
     //     return js.statement('function #(#) { #; }',
     //        [ constructorName, fields,
     //            fields.map(
     //                (name) => js('this.# = #', [name, name]))]));
-    return js('function(#) { #; this.#();}',
-        [fields,
-         fields.map((name) => js('this.# = #', [name, name])),
-         namer.deferredAction]);
+    return js('''function(#, typeInfo) {
+                   #;
+                   if (typeInfo) this.\$builtinTypeInfo = typeInfo;

[herhut, 2015/04/20 10:24:29]

Why not set this unconditionally? Then the instances with and without typeInfo
will get the same map and the value is still undefined if no typeinfo was
provided....

[zarah, 2015/04/20 12:34:50]

There is code depending on whether or not that property is there, so, as
discussed, leaving it for now and added a todo.

+                   this.#();
+                 }''',
+              [fields,
+               fields.map((name) => js('this.# = #', [name, name])),
+               namer.deferredAction]);
   }
 
   jsAst.Expression generateGetter(Element member, String fieldName) {
     ClassElement cls = member.enclosingClass;
     String receiver = backend.isInterceptorClass(cls) ? 'receiver' : 'this';
     List<String> args = backend.isInterceptedMethod(member) ? ['receiver'] : [];
     return js('function(#) { return #.# }', [args, receiver, fieldName]);
   }
 
   jsAst.Expression generateSetter(Element member, String fieldName) {
@@ skipping 242 matching lines @@
           ? function() {
               if (cache === void 0) cache = #tearOff(
                   this, funcs, reflectionInfo, true, [], name).prototype;
               return cache;
             }
           : tearOffGetter(funcs, reflectionInfo, name, isIntercepted);
     }''',  {'tearOff': tearOffAccessExpression});
 
   return <jsAst.Statement>[tearOffGetter, tearOff];
 }