Some build file cleanup

runtime/bin/io_impl_sources.gypi

Index: runtime/bin/io_impl_sources.gypi
diff --git a/runtime/bin/io_impl_sources.gypi b/runtime/bin/io_impl_sources.gypi
index c04cf7d23f17d5621e71b253401e8e3895e75907..8a9c7c5068177c5fb569f7b718d2e43415037272 100644
--- a/runtime/bin/io_impl_sources.gypi
+++ b/runtime/bin/io_impl_sources.gypi
@@ -69,40 +69,6 @@
   ],
   'conditions': [
     ['dart_io_support==1', {
-      'conditions': [
-        ['dart_io_secure_socket==1', {
-          'sources!' : [
-            'io_service_no_ssl.cc',
-            'io_service_no_ssl.h',
-            'secure_socket_unsupported.cc',
-          ],
-          'conditions': [
-            ['dart_io_ssl_builtin_roots==0 or OS=="mac"', {
-              # On Mac, we use the system keystore, so do not compile in the
-              # root certs.
-              'sources!' : [
-                '../../third_party/root_certificates/root_certificates.cc',
-              ],
-            }, { # else dart_io_ssl_builtin_roots == 1 and OS != mac.
-              'sources!' : [
-                'root_certificates_unsupported.cc',
-              ],
-            }],
-          ],
-        }, {  # else dart_io_secure_socket == 0
-          'sources!' : [
-            '../../third_party/root_certificates/root_certificates.cc',
-            'root_certificates_unsupported.cc',
-            'io_service.cc',
-            'io_service.h',
-            'secure_socket.h',
-            'secure_socket_boringssl.cc',
-            'secure_socket_boringssl.h',
-            'secure_socket_macos.cc',
-            'secure_socket_macos.h',
-          ],
-        }],
-      ],
       'sources!' : [
         'filter_unsupported.cc',
         'io_service_unsupported.cc',