Fixes a couple problems with GC of unoptimized code.

runtime/vm/visitor.h

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_VISITOR_H_
 #define VM_VISITOR_H_
 
 #include "vm/globals.h"
+#include "vm/growable_array.h"
 
 namespace dart {
 
 // Forward declarations.
 class Isolate;
 class RawObject;
 
 // An object pointer visitor interface.
 class ObjectPointerVisitor {
  public:
   explicit ObjectPointerVisitor(Isolate* isolate) : isolate_(isolate) {}
   virtual ~ObjectPointerVisitor() {}
 
   Isolate* isolate() const { return isolate_; }
 
   // Range of pointers to visit 'first' <= pointer <= 'last'.
   virtual void VisitPointers(RawObject** first, RawObject** last) = 0;
 
+  virtual bool visit_function_code() const { return true; }
+  virtual GrowableArray<RawFunction*>* skipped_code_functions() {
+    return NULL;
+  }
+
   // len argument is the number of pointers to visit starting from 'p'.
   void VisitPointers(RawObject** p, intptr_t len) {
     VisitPointers(p, (p + len - 1));
   }
 
   void VisitPointer(RawObject** p) { VisitPointers(p , p); }
 
  private:
   Isolate* isolate_;
 
@@ skipping 31 matching lines @@
 
  private:
   Isolate* isolate_;
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(FindObjectVisitor);
 };
 
 }  // namespace dart
 
 #endif  // VM_VISITOR_H_