On-the-fly bookkeeping of PagedSpace memory kept in free-lists.

src/mark-compact.cc

Index: src/mark-compact.cc
diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index 7503f24cb65318bdcd6f91d51a8362095909e0f3..63263ba131c289132d37ddb2fca05b0c6c889cb3 100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -672,8 +672,8 @@ static int FreeListFragmentation(PagedSpace* space, Page* p) {
     return 0;
   }
 
-  FreeList::SizeStats sizes;
-  space->CountFreeListItems(p, &sizes);
+  PagedSpace::SizeStats sizes;
+  space->ObtainFreeListStatistics(p, &sizes);
 
   intptr_t ratio;
   intptr_t ratio_threshold;
@@ -812,8 +812,8 @@ void MarkCompactCollector::CollectEvacuationCandidates(PagedSpace* space) {
       if (!p->WasSwept()) {
         free_bytes = (p->area_size() - p->LiveBytes());
       } else {
-        FreeList::SizeStats sizes;
-        space->CountFreeListItems(p, &sizes);
+        PagedSpace::SizeStats sizes;
+        space->ObtainFreeListStatistics(p, &sizes);
         free_bytes = sizes.Total();
       }