dart2js cps: Remove dart2dart from cps pipeline and clean up.

pkg/compiler/lib/src/tracer.dart

 // Copyright (c) 2014, 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 '../compiler.dart' as api;
 import 'dart:async' show EventSink;
 import 'ssa/ssa.dart' as ssa;
 import 'ssa/ssa_tracer.dart' show HTracer;
@@ skipping 39 matching lines @@
       printProperty("method", methodName);
       printProperty("date", new DateTime.now().millisecondsSinceEpoch);
     });
   }
 
   void traceGraph(String name, var irObject) {
     if (!traceActive) return;
     if (irObject is ssa.HGraph) {
       new HTracer(output, compiler, context).traceGraph(name, irObject);
     }
-    else if (irObject is cps_ir.RootNode) {
+    else if (irObject is cps_ir.FunctionDefinition) {
       new IRTracer(output).traceGraph(name, irObject);
     }
-    else if (irObject is tree_ir.RootNode) {
+    else if (irObject is tree_ir.FunctionDefinition) {
       new TreeTracer(output).traceGraph(name, irObject);
     }
   }
 
   void close() {
     if (output != null) {
       output.close();
     }
   }
 }
@@ skipping 36 matching lines @@
   }
 
   void add(String string) {
     output.add(string);
   }
 
   void addIndent() {
     add(_ind.indentation);
   }
 }