Clean up dump-info and js_backend.

sdk/lib/_internal/compiler/implementation/dump_info.dart

 // Copyright (c) 2013, 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 dump_info;
 
 import 'dart:convert' show
     HtmlEscape,
     JsonEncoder,
     StringConversionSink,
@@ skipping 57 matching lines @@
           innerMapper["$k"] = elementJson;
         }
       });
       json[mapper.name] = innerMapper;
     }
     return json;
   }
 }
 
 class ElementToJsonVisitor extends ElementVisitor<Map<String, dynamic>> {
-  GroupedIdMapper mapper = new GroupedIdMapper();
-  Compiler compiler;
+  final GroupedIdMapper mapper = new GroupedIdMapper();
+  final Compiler compiler;
 
-  Map<Element, Map<String, dynamic>> jsonCache = {};
-  Map<Element, jsAst.Expression> codeCache;
+  final Map<Element, Map<String, dynamic>> jsonCache = {};
 
   int programSize;
   DateTime compilationMoment;
   String dart2jsVersion;
   Duration compilationDuration;
   Duration dumpInfoDuration;
 
-  ElementToJsonVisitor(Compiler compiler) {
-    this.compiler = compiler;
+  ElementToJsonVisitor(this.compiler);
 
+  void run() {
     Backend backend = compiler.backend;
     if (backend is JavaScriptBackend) {
       // Add up the sizes of all output-buffers.
       programSize = backend.emitter.outputBuffers.values.fold(0,
           (a, b) => a + b.length);
     } else {
       programSize = compiler.assembledCode.length;
     }
 
-
     compilationMoment = new DateTime.now();
     dart2jsVersion = compiler.hasBuildId ? compiler.buildId : null;
     compilationDuration = compiler.totalCompileTime.elapsed;
 
     for (var library in compiler.libraryLoader.libraries.toList()) {
       library.accept(this);
     }
 
     dumpInfoDuration = new DateTime.now().difference(compilationMoment);
+
   }
 
   // If keeping the element is in question (like if a function has a size
   // of zero), only keep it if it holds dependencies to elsewhere.
   bool shouldKeep(Element element) {
     return compiler.dumpInfoTask.selectorsFromElement.containsKey(element);
   }
 
   Map<String, dynamic> toJson() {
     return mapper._toJson(this);
@@ skipping 405 matching lines @@
     if (code == null) return null;
     // Concatenate rendered ASTs.
     StringBuffer sb = new StringBuffer();
     for (jsAst.Node ast in code) {
       sb.writeln(jsAst.prettyPrint(ast, compiler).getText());
     }
     return sb;
   }
 
   void collectInfo() {
-    infoCollector = new ElementToJsonVisitor(compiler);
+    infoCollector = new ElementToJsonVisitor(compiler)..run();
   }
 
   void dumpInfo() {
     measure(() {
       if (infoCollector == null) {
         collectInfo();
       }
 
       StringBuffer jsonBuffer = new StringBuffer();
       dumpInfoJson(jsonBuffer);
@@ skipping 66 matching lines @@
     };
 
     outJson['program'] = generalProgramInfo;
 
     ChunkedConversionSink<Object> sink =
       encoder.startChunkedConversion(
           new StringConversionSink.fromStringSink(buffer));
     sink.add(outJson);
   }
 }