Revert of [heap] Refactor evacuation for young and old gen into visitors.

src/heap/mark-compact.h

Index: src/heap/mark-compact.h
diff --git a/src/heap/mark-compact.h b/src/heap/mark-compact.h
index 05cebe1dfcbd42d9d636a37a87426121326d695e..e6723fd70e030d726938337d4294a0d20898d262 100644
--- a/src/heap/mark-compact.h
+++ b/src/heap/mark-compact.h
@@ -327,15 +327,6 @@
 // Mark-Compact collector
 class MarkCompactCollector {
  public:
-  enum IterationMode {
-    kKeepMarking,
-    kClearMarkbits,
-  };
-
-  class EvacuateNewSpaceVisitor;
-  class EvacuateOldSpaceVisitor;
-  class HeapObjectVisitor;
-
   static void Initialize();
 
   void SetUp();
@@ -712,12 +703,13 @@
   // regions to each space's free list.
   void SweepSpaces();
 
-  // Iterates through all live objects on a page using marking information.
-  // Returns whether all objects have successfully been visited.
-  bool IterateLiveObjectsOnPage(MemoryChunk* page, HeapObjectVisitor* visitor,
-                                IterationMode mode);
+  int DiscoverAndEvacuateBlackObjectsOnPage(NewSpace* new_space,
+                                            NewSpacePage* p);
 
   void EvacuateNewSpace();
+
+  bool EvacuateLiveObjectsFromPage(Page* p, PagedSpace* target_space,
+                                   SlotsBuffer** evacuation_slots_buffer);
 
   void AddEvacuationSlotsBufferSynchronized(
       SlotsBuffer* evacuation_slots_buffer);