Use path package in dartdoc

sdk/lib/_internal/dartdoc/bin/dartdoc.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.
 
 /**
  * To generate docs for a library, run this script with the path to an
  * entrypoint .dart file, like:
  *
  *     $ dart dartdoc.dart foo.dart
  *
@@ skipping 27 matching lines @@
 mainWithOptions(Options options) {
   // Need this because ArgParser.getUsage doesn't show command invocation.
   final USAGE = 'Usage dartdoc [options] <entrypoint(s)>\n[options] include:';
 
   final args = options.arguments;
 
   final dartdoc = new Dartdoc();
 
   final argParser = new ArgParser();
 
-  Path libPath = scriptDir.append('../../../../');
+  Path libPath = path.join(scriptDir, '..', '..', '..', '..');
 
   String packageRoot;
 
   argParser.addFlag('no-code',
       help: 'Do not include source code in the documentation.',
       defaultsTo: false, negatable: false,
       callback: (noCode) => dartdoc.includeSource = !noCode);
 
   argParser.addOption('mode', abbr: 'm',
       help: 'Define how HTML pages are generated.',
@@ skipping 129 matching lines @@
 
   // TODO(amouravski): This method is deprecated. Remove on April 22.
   argParser.addOption('pkg',
       help: 'Deprecated: same as --package-root.',
       callback: (packageDir) {
         if(packageDir != null) {
           packageRoot = packageDir;
         }
       });
 
-  dartdoc.dartdocPath = libPath.append('lib/_internal/dartdoc');
+  dartdoc.dartdocPath = path.join(libPath, 'lib', '_internal', 'dartdoc');
 
   if (args.isEmpty) {
     print('No arguments provided.');
     print(USAGE);
     print(argParser.getUsage());
     exit(1);
   }
 
   final entrypoints = <Uri>[];
   try {
@@ skipping 32 matching lines @@
 
   cleanOutputDirectory(dartdoc.outputDir);
 
   // Start the analysis and documentation.
   dartdoc.documentLibraries(entrypoints, libPath, packageRoot)
     // Prepare the dart2js script code and copy static resources.
     // TODO(amouravski): move compileScript out and pre-generate the client
     // scripts. This takes a long time and the js hardly ever changes.
     .then((_) => compileScript(dartdoc.mode, dartdoc.outputDir, libPath,
           dartdoc.tmpPath))
-    .then((_) => copyDirectory(libPath.append('lib/_internal/dartdoc/static'),
-                               dartdoc.outputDir))
+    .then((_) => copyDirectory(
+          path.join(libPath, 'lib', '_internal', 'dartdoc', 'static'),
+          dartdoc.outputDir))
     .then((_) {
       print(dartdoc.status);
       if (dartdoc.totals == 0) {
         exit(1);
       }
     })
     .catchError((e) {
       print('Error: generation failed: ${e}');
       var trace = getAttachedStackTrace(e);
       if (trace != null) print("StackTrace: $trace");
@@ skipping 17 matching lines @@
   // If there is not, then check if the entrypoint is somewhere in a `lib`
   // directory.
   var parts = path.split(path.dirname(script));
   var libDir = parts.lastIndexOf('lib');
   if (libDir > 0) {
     return path.join(path.joinAll(parts.take(libDir)), 'packages');
   } else {
     return null;
   }
 }