Make sure required type arguments are given when using factories.

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

 // Copyright (c) 2012, 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 js_backend;
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
@@ skipping 124 matching lines @@
     nativeEmitter = new NativeEmitter(this);
   }
 
   void addComment(String comment, CodeBuffer buffer) {
     buffer.write(jsAst.prettyPrint(js.comment(comment), compiler));
   }
 
   void computeRequiredTypeChecks() {
     assert(checkedClasses == null && checkedTypedefs == null);
 
-    compiler.codegenWorld.addImplicitChecks(classesUsingTypeVariableTests);
+    backend.rti.addImplicitChecks(compiler.codegenWorld,
+                                  classesUsingTypeVariableTests);
 
     checkedClasses = new Set<ClassElement>();
     checkedTypedefs = new Set<TypedefElement>();
     compiler.codegenWorld.isChecks.forEach((DartType t) {
       if (t is InterfaceType) {
         checkedClasses.add(t.element);
       } else if (t is TypedefType) {
         checkedTypedefs.add(t.element);
       }
     });
@@ skipping 2963 matching lines @@
 """;
 const String HOOKS_API_USAGE = """
 // The code supports the following hooks:
 // dartPrint(message)   - if this function is defined it is called
 //                        instead of the Dart [print] method.
 // dartMainRunner(main) - if this function is defined, the Dart [main]
 //                        method will not be invoked directly.
 //                        Instead, a closure that will invoke [main] is
 //                        passed to [dartMainRunner].
 """;