Additional refactoring for docgen.

pkg/docgen/bin/docgen.dart

Index: pkg/docgen/bin/docgen.dart
diff --git a/pkg/docgen/bin/docgen.dart b/pkg/docgen/bin/docgen.dart
index 2a116de5b1bec5557663576bbb3959b1757c1734..4f79a979afe1dddeb9a2aee5266dd791da3a6669 100644
--- a/pkg/docgen/bin/docgen.dart
+++ b/pkg/docgen/bin/docgen.dart
@@ -32,7 +32,9 @@ void main(List<String> arguments) {
       introFileName: introduction,
       out: results['out'],
       excludeLibraries: excludedLibraries,
-      includeDependentPackages: results['include-dependent-packages']);
+      includeDependentPackages: results['include-dependent-packages'],
+      serve: results['serve'],
+      noDocs: results['no-docs']);
 }
 
 /**
@@ -72,6 +74,11 @@ ArgParser _initArgParser() {
   parser.addFlag('append',
       help: 'Append to the docs folder, library_list.json and index.txt',
       defaultsTo: false, negatable: false);
+  parser.addFlag('serve', help: 'Clone the documentation viewer repo locally '
+      '(if not already present) and start a simple server', defaultsTo: false,
+      negatable: false);
+  parser.addFlag('no-docs', help: 'Do not generate any new documentation',
+      defaultsTo: false, negatable: false);
   parser.addOption('introduction',
       help: 'Adds the provided markdown text file as the introduction'
         ' for the generated documentation.', defaultsTo: '');