Don't try to get the mark bits of the one ptr filler object

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 073bffcf897ea39ee19f19651f7382920f1def04..3bfc2a50f562d1fc67d5b18be933f3d587b5a594 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -6211,6 +6211,7 @@ class UnreachableObjectsFilter : public HeapObjectsFilter {
   }
 
   bool SkipObject(HeapObject* object) {
+    if (object->map() == heap_->one_pointer_filler_map()) return true;

[Hannes Payer (out of office), 2015/07/24 13:25:03]

Object::IsFiller() is the general way to test for filler objects.

     MarkBit mark_bit = Marking::MarkBitFrom(object);
     return Marking::IsWhite(mark_bit);
   }