Add a callback to inform embedders when an isolate is being shut down.

include/dart_api.h

Index: include/dart_api.h
===================================================================
--- include/dart_api.h	(revision 7933)
+++ include/dart_api.h	(working copy)
@@ -435,8 +435,6 @@
  * When the callback is called, Dart_CurrentIsolate can be used to
  * figure out which isolate is being interrupted.
  *
- * \param current_isolate The isolate being interrupted.
- *
  * \return The embedder returns true if the isolate should continue
  *   execution. If the embedder returns false, the isolate will be
  *   unwound (currently unimplemented).
@@ -445,6 +443,26 @@
 // TODO(turnidge): Define and implement unwinding.
 
 /**
+ * An isolate shutdown callback function.
+ *
+ * This callback, provided by the embedder, is called when the vm
+ * shuts down an isolate.
+ *
+ * The isolate may be in the process of shutting down due to an
+ * unrecoverable error, so it is not safe to enter the isolate or use
+ * it to run any Dart code.  No further Dart code will be run on this
+ * isolate by the vm.
+ *
+ * This function should be used to dispose of native resources that
+ * are allocated to an isolate in order to avoid leaks.
+ *
+ * \param callback_data The same callback data which was passed to the
+ *   isolate when it was created.
+ *
+ */
+typedef void (*Dart_IsolateShutdownCallback)(void* callback_data);
+
+/**
  * Initializes the VM.
  *
  * \param create A function to be called during isolate creation.
@@ -455,7 +473,8 @@
  * \return True if initialization is successful.
  */
 DART_EXPORT bool Dart_Initialize(Dart_IsolateCreateCallback create,
-                                 Dart_IsolateInterruptCallback interrupt);
+                                 Dart_IsolateInterruptCallback interrupt,
+                                 Dart_IsolateShutdownCallback shutdown);
 
 /**
  * Sets command line flags. Should be called before Dart_Initialize.