Introduce DartType.unaliased to avoid use of Resolution in the backend.

pkg/compiler/lib/src/js_emitter/native_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 dart2js.js_emitter;
 
 class NativeEmitter {
 
   // TODO(floitsch): the native-emitter should not know about ClassBuilders.
   final Map<Element, full_js_emitter.ClassBuilder> cachedBuilders;
@@ skipping 250 matching lines @@
     FunctionSignature parameters = member.functionSignature;
     Element converter = backend.findHelper('convertDartClosureToJS');
     jsAst.Expression closureConverter =
         emitterTask.staticFunctionAccess(converter);
     parameters.forEachParameter((ParameterElement parameter) {
       String name = parameter.name;
       // If [name] is not in [stubParameters], then the parameter is an optional
       // parameter that was not provided for this stub.
       for (jsAst.Parameter stubParameter in stubParameters) {
         if (stubParameter.name == name) {
-          DartType type = parameter.type.unalias(compiler.resolution);
+          DartType type = parameter.type.unaliased;
           if (type is FunctionType) {
             // The parameter type is a function type either directly or through
             // typedef(s).
             FunctionType functionType = type;
             int arity = functionType.computeArity();
             statements.add(
                 js.statement('# = #(#, $arity)',
                     [name, closureConverter, name]));
             break;
           }
@@ skipping 61 matching lines @@
     // used.  We should also use an interceptor if the check can't be satisfied
     // by a native class in case we get a native instance that tries to spoof
     // the type info.  i.e the criteria for whether or not to use an interceptor
     // is whether the receiver can be native, not the type of the test.
     if (element == null || !element.isClass) return false;
     ClassElement cls = element;
     if (Elements.isNativeOrExtendsNative(cls)) return true;
     return isSupertypeOfNativeClass(element);
   }
 }