Move all flags to CompilerOptions (first step to stop passing the compiler to

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;
@@ skipping 28 matching lines @@
 
   void scan(CompilationUnitElement compilationUnit) {
     measure(() {
       scanElements(compilationUnit);
     });
   }
 
   void scanElements(CompilationUnitElement compilationUnit) {
     Script script = compilationUnit.script;
     Token tokens = new Scanner(script.file,
-        includeComments: compiler.preserveComments).tokenize();
-    if (compiler.preserveComments) {
+        includeComments: compiler.options.preserveComments).tokenize();
+    if (compiler.options.preserveComments) {
       tokens = compiler.processAndStripComments(tokens);
     }
     compiler.dietParser.dietParse(compilationUnit, tokens);
   }
 
   /**
    * Returns the tokens for the [source].
    *
    * The [StringScanner] implementation works on strings that end with a '0'
    * value ('\x00'). If [source] does not end with '0', the string is copied
    * before scanning.
    */
   Token tokenize(String source) {
     return measure(() {
       return new StringScanner.fromString(source, includeComments: false)
           .tokenize();
     });
   }
 }