Add new Dart API call Dart_MakeIsolateRunnable(). This would allow an

runtime/include/dart_api.h

Index: runtime/include/dart_api.h
===================================================================
--- runtime/include/dart_api.h	(revision 20945)
+++ runtime/include/dart_api.h	(working copy)
@@ -827,6 +827,17 @@
  */
 DART_EXPORT void Dart_InterruptIsolate(Dart_Isolate isolate);
 
+
+/**
+ * Make current isolate runnable.
+ *
+ * When isolates are spawned this function is used to indicate that
+ * the creation and initialization (including script loading) of the
+ * isolate is complete and the isolate can start running code.

[Ivan Posva, 2013/04/05 04:18:04]

It is not clear from this description whether the current isolate is exited as
part of this call. The issue is this: As soon as this call is made it is
possible for the thread pool to start dispatching messages. At this point the
thread calling Dart_MakeIsolateRunnable might not have exited the isolate yet.

How about:
bool Dart_IsolateMakeRunnable(Dart_Isolate isolate);

With the precondition being that the isolate is not entered when this call is
made.

+ */
+DART_EXPORT Dart_Handle Dart_MakeIsolateRunnable();
+
+
 // --- Messages and Ports ---
 
 /**