Introduce a lazy-compile stub for functions.

runtime/vm/object.h

Index: runtime/vm/object.h
===================================================================
--- runtime/vm/object.h	(revision 34118)
+++ runtime/vm/object.h	(working copy)
@@ -1491,8 +1491,9 @@
   void set_parameter_names(const Array& value) const;
 
   // Sets function's code and code's function.
-  void SetCode(const Code& value) const;
-  void  ClearCode() const;
+  void AttachCode(const Code& value) const;
+  void set_code(const Code& value) const;
+  void ClearCode() const;
 
   // Disables optimized code and switches to unoptimized code.
   void SwitchToUnoptimizedCode() const;
@@ -1507,7 +1508,7 @@
   static intptr_t unoptimized_code_offset() {
     return OFFSET_OF(RawFunction, unoptimized_code_);
   }
-  inline bool HasCode() const;
+  bool HasCode() const;
 
   // Returns true if there is at least one debugger breakpoint
   // set in this function.
@@ -1991,6 +1992,7 @@
   // RawFunction::VisitFunctionPointers accesses the private constructor of
   // Function.
   friend class RawFunction;
+  friend class MarkingVisitor;  // Access to KindBits
 };
 
 
@@ -2977,9 +2979,6 @@
     return GetBit(index);
   }
 
-  RawCode* Code() const { return raw_ptr()->code_; }
-  void SetCode(const dart::Code& code) const;
-
   intptr_t Length() const { return raw_ptr()->length_; }
 
   uword PC() const { return raw_ptr()->pc_; }
@@ -6632,11 +6631,6 @@
 }
 
 
-bool Function::HasCode() const {
-  return raw_ptr()->code_ != Code::null();
-}
-
-
 intptr_t Field::Offset() const {
   ASSERT(!is_static());  // Offset is valid only for instance fields.
   intptr_t value = Smi::Value(reinterpret_cast<RawSmi*>(raw_ptr()->value_));