- Add different types for persistent and weak persistent handles

runtime/bin/io_buffer.cc

Index: runtime/bin/io_buffer.cc
===================================================================
--- runtime/bin/io_buffer.cc	(revision 23307)
+++ runtime/bin/io_buffer.cc	(working copy)
@@ -10,9 +10,9 @@
 
 Dart_Handle IOBuffer::Allocate(intptr_t size, uint8_t **buffer) {
   uint8_t* data = Allocate(size);
-  Dart_Handle result = Dart_NewExternalTypedData(kUint8,
-                                                 data, size,
-                                                 data, IOBuffer::Finalizer);
+  Dart_Handle result = Dart_NewExternalTypedData(kUint8, data, size);
+  Dart_NewWeakPersistentHandle(result, data, IOBuffer::Finalizer);
+
   if (Dart_IsError(result)) {
     Free(data);
     Dart_PropagateError(result);