Integrate leg as a component in test.py. Also update presubmit script to run tests with leg.

dart/frog/leg/typechecker.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 TypeCheckerTask extends CompilerTask {
   TypeCheckerTask(Compiler compiler) : super(compiler);
   String get name() => "Type checker";
 
   void check(Node tree, Map<Node, Element> elements) {
     measure(() {
@@ skipping 102 matching lines @@
 
   Type visitIdentifier(Identifier node) {
     fail(node);
   }
 
   Type visitSend(Send node) {
     Element target = elements[node];
     if (target !== null) {
       // TODO(karlklose): Move that to a function that also
       // calculates FunctionTypes for other target types.
-      FunctionType funType = target.type;
+      FunctionType funType = target.computeType(compiler, types);
       Link<Type> formals = funType.parameterTypes;
       Link<Node> arguments = node.arguments;
       while ((!formals.isEmpty()) && (!arguments.isEmpty())) {
         compiler.cancel('parameters not supported.');
         var argumentType = visit(arguments.head);
         if (!types.isAssignable(formals.head, argumentType)) {
           var warning = CompilerError.NOT_ASSIGNABLE(argumentType,
                                                      formals.head);
           compiler.reportWarning(node, warning);
         }
@@ skipping 66 matching lines @@
       compiler.cancel('unsupported type ${node.typeName}');
     }
     return types.VOID;
   }
 
   Type visitVariableDefinitions(VariableDefinitions node) {
     // TODO(karlklose): Implement this.
     return types.VOID;
   }
 }