Make isEmpty a getter.

lib/compiler/implementation/ssa/tracer.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.
 
 library tracer;
 
 import 'dart:io';
 import 'ssa.dart';
 import '../js_backend/js_backend.dart';
 import '../dart2jslib.dart';
@@ skipping 32 matching lines @@
 
   void traceGraph(String name, HGraph graph) {
     if (!traceActive) return;
     tag("cfg", () {
       printProperty("name", name);
       visitDominatorTree(graph);
     });
   }
 
   void addPredecessors(HBasicBlock block) {
-    if (block.predecessors.isEmpty()) {
+    if (block.predecessors.isEmpty) {
       printEmptyProperty("predecessors");
     } else {
       addIndent();
       add("predecessors");
       for (HBasicBlock predecessor in block.predecessors) {
         add(' "B${predecessor.id}"');
       }
       add("\n");
     }
   }
 
   void addSuccessors(HBasicBlock block) {
-    if (block.successors.isEmpty()) {
+    if (block.successors.isEmpty) {
       printEmptyProperty("successors");
     } else {
       addIndent();
       add("successors");
       for (HBasicBlock successor in block.successors) {
         add(' "B${successor.id}"');
       }
       add("\n");
     }
   }
@@ skipping 447 matching lines @@
   }
 
   String visitTypeConversion(HTypeConversion node) {
     return "TypeConversion: ${temporaryId(node.checkedInput)} to ${node.type}";
   }
 
   String visitRangeConversion(HRangeConversion node) {
     return "RangeConversion: ${node.checkedInput}";
   }
 }