Move computeType to TypedElement and TypeDeclarationElement.

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 {
 
   final Map<Element, ClassBuilder> cachedBuilders;
 
@@ skipping 325 matching lines @@
       receiver = js('this');
       arguments = argumentsBuffer.sublist(0,
           indexOfLastOptionalArgumentInParameters + 1);
     }
     statements.add(
         js.statement('return #.#(#)', [receiver, target, arguments]));
 
     return statements;
   }
 
-  bool isSupertypeOfNativeClass(Element element) {
-    if (element.isTypeVariable) {
-      compiler.internalError(element, "Is check for type variable.");
-      return false;
-    }
-    if (element.computeType(compiler).unalias(compiler) is FunctionType) {
-      // The element type is a function type either directly or through
-      // typedef(s).
-      return false;
-    }
-
-    if (!element.isClass) {
-      compiler.internalError(element, "Is check does not handle element.");
-      return false;
-    }
-
+  bool isSupertypeOfNativeClass(ClassElement element) {
     if (backend.classesMixedIntoInterceptedClasses.contains(element)) {
       return true;
     }
 
     return subtypes[element] != null;
   }
 
   bool requiresNativeIsCheck(Element element) {
     // TODO(sra): Remove this function.  It determines if a native type may
     // satisfy a check against [element], in which case an interceptor must be
@@ skipping 92 matching lines @@
           }
     ''', {'info': infoAccess,
           'constructor': constructorAccess,
           'subclassRead': subclassRead,
           'interceptorsByTagAccess': interceptorsByTagAccess,
           'leafTagsAccess': leafTagsAccess,
           'nativeSuperclassTagName': embeddedNames.NATIVE_SUPERCLASS_TAG_NAME,
           'allowNativesSubclassing': true});
   }
 }