Refactor the gypi files to eliminate some redundancy.

vm/vm.gypi

 # Copyright (c) 2011, 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.
 
 {
   'variables': {
     'corelib_in_cc_file': 'corelib_in.cc',
     'corelib_cc_file': '<(SHARED_INTERMEDIATE_DIR)/corelib_gen.cc',
     'corelib_impl_in_cc_file': 'corelib_impl_in.cc',
     'corelib_impl_cc_file': '<(SHARED_INTERMEDIATE_DIR)/corelib_impl_gen.cc',
@@ skipping 73 matching lines @@
         '../lib/lib_impl_sources.gypi',
       ],
       'sources': [
         'bootstrap_nocorelib.cc',
       ],
       'include_dirs': [
         '..',
       ],
     },
     {
-      'target_name': 'libdart_api',
-      'type': 'static_library',
-      'include_dirs': [
-        '..',
-      ],
-      'sources': [
-        '../vm/dart_api_impl.cc',
-      ],
-    },
-    {
       'target_name': 'generate_corelib_cc_file',
       'type': 'none',
       'conditions': [
         ['OS=="win"', {
           'msvs_cygwin_dirs': ['<(cygwin_dir)'],
         }],
       ],
       'includes': [
         # Load the runtime implementation sources.
         '../lib/lib_sources.gypi',
@@ skipping 97 matching lines @@
             '--output', '<(snapshot_test_dat_file)',
             '--input_cc', '<(snapshot_test_in_dat_file)',
             '<(snapshot_test_dart_file)',
           ],
           'message': 'Generating ''<(snapshot_test_dat_file)'' file.'
         },
       ]
     },
   ]
 }