Support overriding fields with fields.

dart/lib/compiler/implementation/ssa/codegen.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.
 
 class SsaCodeGeneratorTask extends CompilerTask {
   final JavaScriptBackend backend;
   SsaCodeGeneratorTask(JavaScriptBackend backend)
       : this.backend = backend,
         super(backend.compiler);
   String get name() => 'SSA code generator';
@@ skipping 1489 matching lines @@
       }
       buffer.add('$className.prototype.$methodName.call');
       visitArguments(node.inputs);
     }
     endExpression(JSPrecedence.CALL_PRECEDENCE);
     world.registerStaticUse(superMethod);
   }
 
   visitFieldGet(HFieldGet node) {
     if (!node.isFromActivation()) {
-      String name =
-          compiler.namer.instanceFieldName(currentLibrary, node.name);
+      String name = compiler.namer.getName(node.element);
       beginExpression(JSPrecedence.MEMBER_PRECEDENCE);
       use(node.receiver, JSPrecedence.MEMBER_PRECEDENCE);
       buffer.add('.');
       buffer.add(name);
       beginExpression(JSPrecedence.MEMBER_PRECEDENCE);
     } else {
       use(node.receiver, JSPrecedence.EXPRESSION_PRECEDENCE);
     }
   }
 
   visitFieldSet(HFieldSet node) {
     String name;
     if (!node.isFromActivation()) {
-      name =
-          compiler.namer.instanceFieldName(currentLibrary, node.name);
+      name = compiler.namer.getName(node.element);
       beginExpression(JSPrecedence.ASSIGNMENT_PRECEDENCE);
       use(node.receiver, JSPrecedence.MEMBER_PRECEDENCE);
       buffer.add('.');
       buffer.add(name);
     } else {
       use(node.receiver, JSPrecedence.EXPRESSION_PRECEDENCE);
     }
     buffer.add(' = ');
     use(node.value, JSPrecedence.ASSIGNMENT_PRECEDENCE);
     if (node.receiver !== null) {
@@ skipping 1038 matching lines @@
       startBailoutSwitch();
     }
   }
 
   void endLabeledBlock(HLabeledBlockInformation labeledBlockInfo) {
     if (labeledBlockInfo.body.start.hasGuards()) {
       endBailoutSwitch();
     }
   }
 }