Pass ClosedWorld directly to codegen tasks

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 'dart:async' show EventSink;
 
 import '../compiler.dart' as api;
-import 'compiler.dart' show Compiler;
+import 'js_backend/namer.dart' show Namer;
 import 'ssa/nodes.dart' as ssa show HGraph;
 import 'ssa/ssa_tracer.dart' show HTracer;
 import 'util/util.dart' show Indentation;
+import 'world.dart' show ClosedWorld;
 
 /**
  * If non-null, we only trace methods whose name match the regexp defined by the
  * given pattern.
  */
 const String TRACE_FILTER_PATTERN = const String.fromEnvironment("DUMP_IR");
 
 final RegExp TRACE_FILTER =
     TRACE_FILTER_PATTERN == null ? null : new RegExp(TRACE_FILTER_PATTERN);
 
 /**
  * Dumps the intermediate representation after each phase in a format
  * readable by IR Hydra.
  */
 class Tracer extends TracerUtil {
-  final Compiler compiler;
+  final ClosedWorld closedWorld;
+  final Namer namer;
   bool traceActive = false;
   final EventSink<String> output;
   final bool isEnabled = TRACE_FILTER != null;
 
-  Tracer(Compiler compiler, api.CompilerOutputProvider outputProvider)
-      : this.compiler = compiler,
-        output = TRACE_FILTER != null ? outputProvider('dart', 'cfg') : null;
+  Tracer(
+      this.closedWorld, this.namer, api.CompilerOutputProvider outputProvider)
+      : output = TRACE_FILTER != null ? outputProvider('dart', 'cfg') : null;
 
   void traceCompilation(String methodName) {
     if (!isEnabled) return;
     traceActive = TRACE_FILTER.hasMatch(methodName);
     if (!traceActive) return;
     tag("compilation", () {
       printProperty("name", methodName);
       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).traceGraph(name, irObject);
+      new HTracer(output, closedWorld, namer).traceGraph(name, irObject);
     }
   }
 
   void close() {
     if (output != null) {
       output.close();
     }
   }
 }
 
@@ skipping 34 matching lines @@
   }
 
   void add(String string) {
     output.add(string);
   }
 
   void addIndent() {
     add(_ind.indentation);
   }
 }