Fix NoTrackDoubleFieldsForSerializerScope.

src/bootstrapper.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2548 matching lines @@
 class NoTrackDoubleFieldsForSerializerScope {
  public:
   NoTrackDoubleFieldsForSerializerScope() : flag_(FLAG_track_double_fields) {
     if (Serializer::enabled()) {
       // Disable tracking double fields because heap numbers treated as
       // immutable by the serializer.
       FLAG_track_double_fields = false;
     }
   }
   ~NoTrackDoubleFieldsForSerializerScope() {
-    FLAG_track_double_fields = flag_;
+    if (Serializer::enabled()) {
+      FLAG_track_double_fields = flag_;
+    }
   }
 
  private:
   bool flag_;
 };
 
 
 Genesis::Genesis(Isolate* isolate,
                  Handle<Object> global_object,
                  v8::Handle<v8::ObjectTemplate> global_template,
@@ skipping 151 matching lines @@
   return from + sizeof(NestingCounterType);
 }
 
 
 // Called when the top-level V8 mutex is destroyed.
 void Bootstrapper::FreeThreadResources() {
   ASSERT(!IsActive());
 }
 
 } }  // namespace v8::internal