Add deoptimization history to optimized functions.

runtime/vm/object.h

Index: runtime/vm/object.h
===================================================================
--- runtime/vm/object.h	(revision 23072)
+++ runtime/vm/object.h	(working copy)
@@ -1278,6 +1278,9 @@
   static intptr_t code_offset() { return OFFSET_OF(RawFunction, code_); }
   inline bool HasCode() const;
 
+  RawArray* deopt_history() const { return raw_ptr()->deopt_history_; }
+  void set_deopt_history(const Array& value) const;
+
   // Returns true if there is at least one debugger breakpoint
   // set in this function.
   bool HasBreakpoint() const;