Switch UnreachableObjectsFilter to use Marking instead of InstrusiveMarking.

src/mark-compact.h

Index: src/mark-compact.h
diff --git a/src/mark-compact.h b/src/mark-compact.h
index 968bf70eb973b19e9231a7cd9f30e2a2585a56ff..0a3d38229f8713ecd82019759cf0c54f0892a673 100644
--- a/src/mark-compact.h
+++ b/src/mark-compact.h
@@ -538,6 +538,18 @@ class MarkCompactCollector {
 
   void InvalidateCode(Code* code);
 
+  void ClearMarkbits();
+
+  void TaintMarkbits() {

[Erik Corry, 2011/10/19 17:56:07]

I think it would be preferable with a SetTaintMarkbits(bool value)

+    markbits_are_tainted_ = true;
+  }
+
+  bool AreMarkbitsTainted() {
+    return markbits_are_tainted_;
+  }
+
+  static inline bool IsLiveBytesUpdateRequired(HeapObject* obj);
+
  private:
   MarkCompactCollector();
   ~MarkCompactCollector();
@@ -574,6 +586,8 @@ class MarkCompactCollector {
 
   bool collect_maps_;
 
+  bool markbits_are_tainted_;
+
   // A pointer to the current stack-allocated GC tracer object during a full
   // collection (NULL before and after).
   GCTracer* tracer_;
@@ -717,7 +731,6 @@ class MarkCompactCollector {
 
   void SweepSpace(PagedSpace* space, SweeperType sweeper);
 
-
 #ifdef DEBUG
   // -----------------------------------------------------------------------
   // Debugging variables, functions and classes