Change RecordSlot interface. Make it more robust by replacing anchor slot with actual object.

src/heap/mark-compact-inl.h

Index: src/heap/mark-compact-inl.h
diff --git a/src/heap/mark-compact-inl.h b/src/heap/mark-compact-inl.h
index de8df3d77acdfe94c83b4cb98796a327d2024f9c..c78ae650df9ffea23cd42705abdc4d60f75fb09c 100644
--- a/src/heap/mark-compact-inl.h
+++ b/src/heap/mark-compact-inl.h
@@ -55,15 +55,15 @@ bool MarkCompactCollector::IsMarked(Object* obj) {
 }
 
 
-void MarkCompactCollector::RecordSlot(Object** anchor_slot, Object** slot,
-                                      Object* object,
+void MarkCompactCollector::RecordSlot(HeapObject* object, Object** slot,
+                                      Object* target,
                                       SlotsBuffer::AdditionMode mode) {
-  Page* object_page = Page::FromAddress(reinterpret_cast<Address>(object));
-  if (object_page->IsEvacuationCandidate() &&
-      !ShouldSkipEvacuationSlotRecording(anchor_slot)) {
+  Page* target_page = Page::FromAddress(reinterpret_cast<Address>(target));
+  if (target_page->IsEvacuationCandidate() &&
+      !ShouldSkipEvacuationSlotRecording(object)) {
     if (!SlotsBuffer::AddTo(&slots_buffer_allocator_,
-                            object_page->slots_buffer_address(), slot, mode)) {
-      EvictPopularEvacuationCandidate(object_page);
+                            target_page->slots_buffer_address(), slot, mode)) {
+      EvictPopularEvacuationCandidate(target_page);
     }
   }
 }