More changes to use #ifndef PRODUCT ... #endif explicitly instead of relying on compiler magic.

runtime/vm/gc_marker.cc

 // 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.
 
 #include "vm/gc_marker.h"
 
 #include "vm/allocation.h"
 #include "vm/dart_api_state.h"
 #include "vm/isolate.h"
 #include "vm/log.h"
@@ skipping 516 matching lines @@
       if (raw_obj->IsOldObject() && !raw_obj->IsMarked()) {
         // Object has become garbage. Replace it will null.
         *current = Object::null();
       }
     }
   }
 };
 
 
 void GCMarker::ProcessObjectIdTable(Isolate* isolate) {
+#ifndef PRODUCT
   if (!FLAG_support_service) {
     return;
   }
   ObjectIdRingClearPointerVisitor visitor(isolate);
   ObjectIdRing* ring = isolate->object_id_ring();
   ASSERT(ring != NULL);
   ring->VisitPointers(&visitor);
+#endif  // !PRODUCT
 }
 
 
 class MarkTask : public ThreadPool::Task {
  public:
   MarkTask(GCMarker* marker,
            Isolate* isolate,
            Heap* heap,
            PageSpace* page_space,
            MarkingStack* marking_stack,
@@ skipping 223 matching lines @@
       // Phase 3: Finalize results from all markers (detach code, etc.).
       barrier.Exit();
     }
     ProcessWeakTables(page_space);
     ProcessObjectIdTable(isolate);
   }
   Epilogue(isolate, invoke_api_callbacks);
 }
 
 }  // namespace dart