Remove dependency on dart:json.

dart/lib/compiler/implementation/scanner/scanner_task.dart

 // Copyright (c) 2012, 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 scanner;
 
 class ScannerTask extends CompilerTask {
   ScannerTask(Compiler compiler) : super(compiler);
   String get name => 'Scanner';
 
   void scanLibrary(LibraryElement library) {
     var compilationUnit = library.entryCompilationUnit;
-    compiler.log("scanning library ${compilationUnit.script.name}");
+    var canonicalUri = library.uri.toString();
+    var resolvedUri = compilationUnit.script.uri.toString();
+    if (canonicalUri == resolvedUri) {
+      compiler.log("scanning library $canonicalUri");
+    } else {
+      compiler.log("scanning library $canonicalUri ($resolvedUri)");
+    }
     scan(compilationUnit);
   }
 
   void scan(CompilationUnitElement compilationUnit) {
     measure(() {
       scanElements(compilationUnit);
     });
   }
 
   void scanElements(CompilationUnitElement compilationUnit) {
@@ skipping 10 matching lines @@
   dietParse(CompilationUnitElement compilationUnit, Token tokens) {
     measure(() {
       Function idGenerator = compiler.getNextFreeClassId;
       ElementListener listener =
           new ElementListener(compiler, compilationUnit, idGenerator);
       PartialParser parser = new PartialParser(listener);
       parser.parseUnit(tokens);
     });
   }
 }