Adding embedder API function Dart_FinalizeLoading

runtime/include/dart_api.h

Index: runtime/include/dart_api.h
===================================================================
--- runtime/include/dart_api.h	(revision 37402)
+++ runtime/include/dart_api.h	(working copy)
@@ -2645,6 +2645,18 @@
                                               Dart_Handle patch_source);
 
 
+/**
+ * Indicates that all outstanding load requests have been satisfied,
+ * finalizing classes and completing deferred library futures.
+ *
+ * Requires there to be a current isolate.
+ *
+ * \return Success if all deferred library futures are completed.
+ *   Otherwise, returns an error.
+ */
+DART_EXPORT Dart_Handle Dart_FinalizeLoading();
+
+
 /*
  * =====
  * Peers