Implement map collection for incremental marking.

src/incremental-marking.h

Index: src/incremental-marking.h
diff --git a/src/incremental-marking.h b/src/incremental-marking.h
index 8cbe6c18e7bd5631709982770ae35dfd02f6426c..024ef6a791457773683065fae77f371765cec3b6 100644
--- a/src/incremental-marking.h
+++ b/src/incremental-marking.h
@@ -1,4 +1,4 @@
-// Copyright 2011 the V8 project authors. All rights reserved.
+// Copyright 2012 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:
@@ -169,6 +169,16 @@ class IncrementalMarking {
     return true;
   }
 
+  // Marks the object grey and pushes it on the marking stack.
+  // Returns true if object needed marking and false otherwise.
+  // This is for incremental marking only.
+  INLINE(bool MarkObject(HeapObject* obj));
+
+  // Marks the object black without pushing it on the marking stack.
+  // Returns true if object needed marking and false otherwise.
+  // This is for incremental marking only.
+  INLINE(bool MarkObjectWithoutPush(HeapObject* obj));
+
   inline int steps_count() {
     return steps_count_;
   }
@@ -260,6 +270,7 @@ class IncrementalMarking {
   VirtualMemory* marking_deque_memory_;
   bool marking_deque_memory_committed_;
   MarkingDeque marking_deque_;
+  Marker<IncrementalMarking> marker_;
 
   int steps_count_;
   double steps_took_;