Make --trace-loading great again.

runtime/bin/vmservice/loader.dart

 // Copyright (c) 2015, 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.
 
 part of vmservice_io;
 
 _sanitizeWindowsPath(path) {
   // For Windows we need to massage the paths a bit according to
   // http://blogs.msdn.com/b/ie/archive/2006/12/06/file-uris-in-windows.aspx
   //
@@ skipping 44 matching lines @@
 
 class FileRequest {
   final SendPort sp;
   final int tag;
   final Uri uri;
   final Uri resolvedUri;
   final String libraryUrl;
   FileRequest(this.sp, this.tag, this.uri, this.resolvedUri, this.libraryUrl);
 }
 
+bool _traceLoading = false;
+
 // State associated with the isolate that is used for loading.
 class IsolateLoaderState extends IsolateEmbedderData {
   IsolateLoaderState(this.isolateId);
 
   final int isolateId;
 
   SendPort sp;
 
   void init(String packageRootFlag, String packagesConfigFlag,
       String workingDirectory, String rootScript) {
@@ skipping 19 matching lines @@
       _packagesPort = null;
     }
   }
 
   // The working directory when the embedder started.
   Uri _workingDirectory;
 
   // The root script's uri.
   Uri _rootScript;
 
-  bool _traceLoading = false;
-
   // Packages are either resolved looking up in a map or resolved from within a
   // package root.
   bool get _packagesReady =>
       (_packageRoot != null) ||
       (_packageMap != null) ||
       (_packageError != null);
 
   // Error string set if there was an error resolving package configuration.
   // For example not finding a .packages file or packages/ directory, malformed
   // .packages file or any other related error.
@@ skipping 1023 matching lines @@
         msg[2] = resolvedUri.toString();
         msg[3] = null;
         msg[4] = e.toString();
         sp.send(msg);
       }
       break;
     default:
       _log('Unknown loader request tag=$tag from $isolateId');
   }
 }