remove docgen from the sdk, and generating docs with docgen

dart.gyp

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'most',
       'type': 'none',
       'dependencies': [
@@ skipping 76 matching lines @@
       # We have this additional target because the try target takes to long
       # to build in debug mode and will make the build step time out.
       'target_name': 'dart2js_bot_debug',
       'type': 'none',
       'dependencies': [
         'create_sdk',
         'packages',
       ],
     },
     {
-      'target_name': 'api_docs',
-      'type': 'none',
-      'dependencies': [
-        'utils/apidoc/docgen.gyp:dartdocgen',
-      ],
-    },
-    {
       'target_name': 'samples',
       'type': 'none',
       'dependencies': [],
       'conditions': [
         ['OS!="android"', {
            'dependencies': [
              'runtime/dart-runtime.gyp:sample_extension',
            ],
           },
         ],
       ]
     },
     {
       'target_name': 'packages',
       'type': 'none',
       'dependencies': [
         'pkg/pkg.gyp:pkg_packages',
       ],
     },
     {
       'target_name': 'try',
       'type': 'none',
       'dependencies': [
         'site/try/build_try.gyp:try_site',
       ],
     },
   ],
 }