Deoptimization can occur at Dart calls (includes native calls to C) but not at runtime calls. This …

runtime/vm/flow_graph_compiler.cc

Index: runtime/vm/flow_graph_compiler.cc
===================================================================
--- runtime/vm/flow_graph_compiler.cc	(revision 11533)
+++ runtime/vm/flow_graph_compiler.cc	(working copy)
@@ -239,10 +239,9 @@
   // information.
   const intptr_t deopt_index = deopt_stubs_.length();
   AddDeoptStub(deopt_id, kDeoptAtCall);
-  pc_descriptors_list()->AddDescriptor(PcDescriptors::kDeoptIndex,
-                                       assembler()->CodeSize(),
+  pc_descriptors_list()->AddDeoptIndex(assembler()->CodeSize(),
                                        deopt_id,
-                                       token_pos,
+                                       kDeoptAtCall,
                                        deopt_index);
 }