Make CompilerTask independent of compiler.

pkg/compiler/lib/src/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.
 
 library dart2js.scanner.task;
 
-import '../common/tasks.dart' show CompilerTask;
-import '../compiler.dart' show Compiler;
+import '../common/tasks.dart' show CompilerTask, Measurer;
+import '../diagnostics/diagnostic_listener.dart' show DiagnosticReporter;
 import '../elements/elements.dart' show CompilationUnitElement, LibraryElement;
 import '../script.dart' show Script;
 import '../parser/diet_parser_task.dart' show DietParserTask;
 import '../tokens/token.dart' show Token;
 import '../tokens/token_constants.dart' as Tokens show COMMENT_TOKEN, EOF_TOKEN;
 import '../tokens/token_map.dart' show TokenMap;
 
 import 'scanner.dart' show Scanner;
 import 'string_scanner.dart' show StringScanner;
 
 class ScannerTask extends CompilerTask {
   final DietParserTask _dietParser;
   final bool _preserveComments;
   final TokenMap _commentMap;
+  final DiagnosticReporter reporter;
 
-  ScannerTask(Compiler compiler, this._dietParser,
+  ScannerTask(this._dietParser, this.reporter, Measurer measurer,
       {bool preserveComments: false, TokenMap commentMap})
       : _preserveComments = preserveComments,
         _commentMap = commentMap,
-        super(compiler) {
+        super(measurer) {
     if (_preserveComments && _commentMap == null) {
       throw new ArgumentError(
           "commentMap must be provided if preserveComments is true");
     }
   }
 
   String get name => 'Scanner';
 
   void scanLibrary(LibraryElement library) {
     CompilationUnitElement compilationUnit = library.entryCompilationUnit;
@@ skipping 52 matching lines @@
         } else {
           prevToken.next = currentToken;
         }
       }
       prevToken = currentToken;
       currentToken = currentToken.next;
     }
     return firstToken;
   }
 }