Adjusts dart2js backend to handle method type arguments.

pkg/compiler/lib/src/resolution/signatures.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.
 
 library dart2js.resolution.signatures;
 
 import '../common.dart';
 import '../compiler.dart' show Compiler;
 import '../dart_types.dart';
 import '../elements/elements.dart';
@@ skipping 296 matching lines @@
 
       // Create the types and elements corresponding to [typeVariableNodes].
       Link<Node> nodes = typeVariableNodes.nodes;
       List<DartType> arguments =
           new List.generate(nodes.slowLength(), (int index) {
         TypeVariable node = nodes.head;
         String variableName = node.name.source;
         nodes = nodes.tail;
         TypeVariableElementX variableElement =
             new TypeVariableElementX(variableName, element, index, node);
-        // TODO(eernst): When type variables are implemented fully we will need
-        // to resolve the actual bounds; currently we just claim [dynamic].
+        // GENERIC_METHODS: When method type variables are implemented fully we
+        // must resolve the actual bounds; currently we just claim that
+        // every method type variable has upper bound [dynamic].
         variableElement.boundCache = const DynamicType();
-        TypeVariableType variableType = new TypeVariableType(variableElement);
+        TypeVariableType variableType =
+            new MethodTypeVariableType(variableElement);
         variableElement.typeCache = variableType;
         return variableType;
       }, growable: false);
       return arguments;
     }
 
     List<DartType> typeVariableTypes = createTypeVariables(typeVariables);
     scope = new FunctionSignatureBuildingScope(scope, typeVariableTypes);
     SignatureResolver visitor = new SignatureResolver(
         compiler, element, scope, registry,
@@ skipping 142 matching lines @@
 /// variables of the function signature itself when its signature is analyzed.
 class FunctionSignatureBuildingScope extends TypeVariablesScope {
   @override
   final List<DartType> typeVariables;
 
   FunctionSignatureBuildingScope(Scope parent, this.typeVariables)
       : super(parent);
 
   String toString() => 'FunctionSignatureBuildingScope($typeVariables)';
 }