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

pkg/compiler/lib/src/native/native.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 native;
 
 import '../compiler.dart' show Compiler;
 import '../elements/elements.dart';
 
 export 'behavior.dart';
@@ skipping 12 matching lines @@
       || libraryName == 'dart:async'
       || libraryName == 'dart:html'
       || libraryName == 'dart:html_common'
       || libraryName == 'dart:indexed_db'
       || libraryName == 'dart:js'
       || libraryName == 'dart:svg'
       || libraryName == 'dart:_native_typed_data'
       || libraryName == 'dart:web_audio'
       || libraryName == 'dart:web_gl'
       || libraryName == 'dart:web_sql'
-      || compiler.allowNativeExtensions) {
+      || compiler.options.allowNativeExtensions) {
     return true;
   }
   return false;
 }