Split dart_api.h into multiple parts:

runtime/dart-runtime.gyp

 # 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.
 
 {
   'includes': [
     'tools/gyp/runtime-configurations.gypi',
     'vm/vm.gypi',
     'bin/bin.gypi',
     'third_party/double-conversion/src/double-conversion.gypi',
@@ skipping 32 matching lines @@
         'libjscre',
         'libdouble_conversion',
         'generate_version_cc_file',
       ],
       'include_dirs': [
         '.',
       ],
       'sources': [
         'include/dart_api.h',
         'include/dart_debugger_api.h',
+        'include/dart_mirror_api.h',
+        'include/dart_native_api.h',
         'vm/dart_api_impl.cc',
         'vm/debugger_api_impl.cc',
+        'vm/mirrors_api_impl.cc',
+        'vm/native_api_impl.cc',
         'vm/version.h',
         '<(version_cc_file)',
       ],
       'defines': [
         # The only effect of DART_SHARED_LIB is to export the Dart API entries.
         'DART_SHARED_LIB',
       ],
       'direct_dependent_settings': {
         'include_dirs': [
           'include',
@@ skipping 60 matching lines @@
     },
     {
       'target_name': 'runtime_packages',
       'type': 'none',
       'dependencies': [
         '../pkg/pkg.gyp:pkg_packages',
       ],
     },
   ],
 }