Switch UnreachableObjectsFilter to use Marking instead of InstrusiveMarking.

src/incremental-marking.cc

Index: src/incremental-marking.cc
diff --git a/src/incremental-marking.cc b/src/incremental-marking.cc
index d0d3354b800e3eb5f228f7bde7a941bddef6ad9f..c17c8b6bafa59902406fc1c9ccbb083a6c791511 100644
--- a/src/incremental-marking.cc
+++ b/src/incremental-marking.cc
@@ -469,6 +469,8 @@ void IncrementalMarking::StartMarking(CompactionFlag flag) {
 
   ActivateIncrementalWriteBarrier();
 
+  heap_->mark_compact_collector()->ClearMarkbits();

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

I don't understand why this is now needed in the incremental case.  It seems to
me that it might cause a longer pause than necessary.

+
 #ifdef DEBUG
   // Marking bits are cleared by the sweeper.
   heap_->mark_compact_collector()->VerifyMarkbitsAreClean();