Support for parsing all CSS and producing one CSS file

lib/src/files.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 files;
 
 import 'package:html5lib/dom.dart';
 import 'file_system/path.dart';
 import 'info.dart';
 
 /** An input file to process by the template compiler. */
 class SourceFile {
+  static const int HTML = 1;
+  static const int DART = 2;
+  static const int STYLESHEET = 3;
+
   final Path path;
+  final int type;
 
-  final bool isDart;
   Document document;
+
+  /** Dart code or contents of a linked style sheet. */
   String code;
 
-  SourceFile(this.path, {this.isDart: false});
+  SourceFile(this.path, {this.type: HTML});
+
+  bool get isDart => type == DART;
+  bool get isHtml => type == HTML;
+  bool get isStyleSheet => type == STYLESHEET;
 
   String toString() => "<#SourceFile $path>";
 }
 
 /** An output file to generated by the template compiler. */
 class OutputFile {
   final Path path;
   final String contents;
 
   /**
    * Path to the source file that was transformed into this OutputFile, `null`
    * for files that are generated and do not correspond to an input
    * [SourceFile].
    */
   final Path source;
 
   OutputFile(this.path, this.contents, {Path source})
       : source = source;
 }