Make dart:_vmservice a proper builtin library

runtime/lib/vmservice_sources.gypi

Index: runtime/lib/vmservice_sources.gypi
diff --git a/runtime/lib/vmservice_sources.gypi b/runtime/lib/vmservice_sources.gypi
new file mode 100644
index 0000000000000000000000000000000000000000..e60a4c8830e5b2a04405cc78e7f63412dad0d60c
--- /dev/null
+++ b/runtime/lib/vmservice_sources.gypi
@@ -0,0 +1,18 @@
+# Copyright (c) 2015, 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.
+
+# Sources that make up the library "dart:_vmservice".
+
+{
+  'sources': [
+    'vmservice/vmservice.dart',
+    # The above file needs to be first as it imports required libraries.
+    'vmservice/client.dart',
+    'vmservice/constants.dart',
+    'vmservice/running_isolate.dart',
+    'vmservice/running_isolates.dart',
+    'vmservice/message.dart',
+    'vmservice/message_router.dart',
+  ],
+}