Move IncrementalRecordWrite to a stub.

src/heap.cc

 // Copyright 2010 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 483 matching lines @@
         : &Counters::gc_compactor;
     rate->Start();
     next_gc_likely_to_collect_more =
         PerformGarbageCollection(collector, &tracer);
     rate->Stop();
 
     GarbageCollectionEpilogue();
   }
 
   ASSERT(IncrementalMarking::state() == IncrementalMarking::STOPPED);
-  if (NextGCIsLikelyToBeFull() && FLAG_incremental_marking) {
+  if (IncrementalMarking::WorthActivating() && NextGCIsLikelyToBeFull()) {
     IncrementalMarking::Start();
   }
 
 #ifdef ENABLE_LOGGING_AND_PROFILING
   if (FLAG_log_gc) HeapProfiler::WriteSample();
   if (CpuProfiler::is_profiling()) CpuProfiler::ProcessMovedFunctions();
 #endif
 
   return next_gc_likely_to_collect_more;
 }
@@ skipping 5069 matching lines @@
 void ExternalStringTable::TearDown() {
   new_space_strings_.Free();
   old_space_strings_.Free();
 }
 
 
 List<Object*> ExternalStringTable::new_space_strings_;
 List<Object*> ExternalStringTable::old_space_strings_;
 
 } }  // namespace v8::internal