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

pkg/compiler/lib/src/js/js.dart

 // Copyright (c) 2015, 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 js;
 
 import 'package:js_ast/js_ast.dart';
 export 'package:js_ast/js_ast.dart';
 
 import '../common.dart';
 import '../compiler.dart' show
     Compiler;
 import '../dump_info.dart' show
     DumpInfoTask;
 import '../io/code_output.dart' show
     CodeBuffer,
     CodeOutput;
 import '../js_emitter/js_emitter.dart' show
     USE_LAZY_EMITTER;
 
 import 'js_source_mapping.dart';
 
 String prettyPrint(
     Node node,
     Compiler compiler,
     {bool allowVariableMinification: true,
      Renamer renamerForNames: JavaScriptPrintingOptions.identityRenamer}) {
   // TODO(johnniwinther): Do we need all the options here?
   JavaScriptPrintingOptions options = new JavaScriptPrintingOptions(
-      shouldCompressOutput: compiler.enableMinification,
+      shouldCompressOutput: compiler.options.enableMinification,
       minifyLocalVariables: allowVariableMinification,
       preferSemicolonToNewlineInMinifiedOutput: USE_LAZY_EMITTER,
       renamerForNames: renamerForNames);
   SimpleJavaScriptPrintingContext context =
       new SimpleJavaScriptPrintingContext();
   Printer printer = new Printer(options, context);
   printer.visit(node);
   return context.getText();
 }
 
 CodeBuffer createCodeBuffer(
     Node node,
     Compiler compiler,
     {DumpInfoTask monitor,
      bool allowVariableMinification: true,
      Renamer renamerForNames: JavaScriptPrintingOptions.identityRenamer}) {
   JavaScriptSourceInformationStrategy sourceInformationFactory =
       compiler.backend.sourceInformationStrategy;
   JavaScriptPrintingOptions options = new JavaScriptPrintingOptions(
-      shouldCompressOutput: compiler.enableMinification,
+      shouldCompressOutput: compiler.options.enableMinification,
       minifyLocalVariables: allowVariableMinification,
       preferSemicolonToNewlineInMinifiedOutput: USE_LAZY_EMITTER,
       renamerForNames: renamerForNames);
   CodeBuffer outBuffer = new CodeBuffer();
   SourceInformationProcessor sourceInformationProcessor =
         sourceInformationFactory.createProcessor(
             new SourceLocationsMapper(outBuffer));
   Dart2JSJavaScriptPrintingContext context =
       new Dart2JSJavaScriptPrintingContext(
           compiler.reporter, monitor, outBuffer, sourceInformationProcessor);
@@ skipping 142 matching lines @@
   }
   if (node is PropertyAccess) {
     PropertyAccess access = node;
     if (access.receiver is InterpolatedExpression) {
       InterpolatedExpression hole = access.receiver;
       return hole.isPositional && hole.nameOrPosition == 0;
     }
   }
   return false;
 }