Traverse inlined frames lazily when printing the stacktrace.

runtime/vm/object_store.cc

Index: runtime/vm/object_store.cc
===================================================================
--- runtime/vm/object_store.cc	(revision 27140)
+++ runtime/vm/object_store.cc	(working copy)
@@ -129,16 +129,13 @@
     return false;
   }
   set_out_of_memory(Instance::Cast(result));
-  const Array& func_array = Array::Handle(
-      isolate,
-      Array::New(Stacktrace::kPreallocatedStackdepth, Heap::kOld));
   const Array& code_array = Array::Handle(
       isolate,
       Array::New(Stacktrace::kPreallocatedStackdepth, Heap::kOld));
   const Array& pc_offset_array = Array::Handle(
       isolate,
       Array::New(Stacktrace::kPreallocatedStackdepth, Heap::kOld));
-  result = Stacktrace::New(func_array, code_array, pc_offset_array);
+  result = Stacktrace::New(code_array, pc_offset_array);
   set_preallocated_stack_trace(Stacktrace::Cast(result));
 
   return true;