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

pkg/compiler/lib/src/scanner/scanner_task.dart

Index: pkg/compiler/lib/src/scanner/scanner_task.dart
diff --git a/pkg/compiler/lib/src/scanner/scanner_task.dart b/pkg/compiler/lib/src/scanner/scanner_task.dart
index 17b3dbc2407b11a5b65030a23087345e74859dbc..98be8201b8afaf9d83cd00227098e2b0afcae923 100644
--- a/pkg/compiler/lib/src/scanner/scanner_task.dart
+++ b/pkg/compiler/lib/src/scanner/scanner_task.dart
@@ -46,8 +46,8 @@ class ScannerTask extends CompilerTask {
   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);