Fix for issues 6080 - pass in the Isolate's top context into the stub for invoking dart code from n…

runtime/vm/stack_frame.cc

Index: runtime/vm/stack_frame.cc
===================================================================
--- runtime/vm/stack_frame.cc	(revision 18203)
+++ runtime/vm/stack_frame.cc	(working copy)
@@ -35,6 +35,11 @@
 }
 
 
+RawContext* EntryFrame::SavedContext() const {
+  return *(reinterpret_cast<RawContext**>(fp() + SavedContextOffset()));
+}
+
+
 void EntryFrame::VisitObjectPointers(ObjectPointerVisitor* visitor) {
   // Visit objects between SP and (FP - callee_save_area).
   ASSERT(visitor != NULL);