Address review comments from https://chromiumcodereview.appspot.com/10454049/.

lib/compiler/implementation/ssa/tracer.dart

 // Copyright (c) 2011, 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('../leg.dart');
 
 final bool GENERATE_SSA_TRACE = false;
 
 class HTracer extends HGraphVisitor implements Tracer {
   int indent = 0;
   final RandomAccessFile output;
   final bool enabled = GENERATE_SSA_TRACE;
 
   HTracer([String path = "dart.cfg"])
       : output = GENERATE_SSA_TRACE ? new File(path).openSync(FileMode.WRITE)
                                     : null;
 
   void close() {
     if (enabled) output.closeSync();
   }
 
-  String method;
   void traceCompilation(String methodName) {
     tag("compilation", () {
       printProperty("name", methodName);
       printProperty("method", methodName);
       printProperty("date", new Date.now().value);
     });
   }
 
   void traceGraph(String name, HGraph graph) {
     if (!enabled) return;
@@ skipping 405 matching lines @@
   String visitIs(HIs node) {
     String type = node.typeExpression.toString();
     return "TypeTest: ${temporaryId(node.expression)} is $type";
   }
 
   String visitTypeConversion(HTypeConversion node) {
     String type = node.propagatedType.toString();
     return "TypeConversion: ${temporaryId(node.inputs[0])} to $type";
   }
 }