Reland "[heap] Unify evacuating an object for new and old generation."

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 25f09a7be1db1e286b5b7d20bea95819d50ebccd..328fcaaed00408d80e6cfc9ef92130c3fcb8a73c 100644
--- a/src/heap/mark-compact.h
+++ b/src/heap/mark-compact.h
@@ -319,10 +319,6 @@ class MarkCompactCollector {
     kClearMarkbits,
   };
 
-  class EvacuateNewSpaceVisitor;
-  class EvacuateOldSpaceVisitor;
-  class HeapObjectVisitor;
-
   static void Initialize();
 
   void SetUp();
@@ -409,8 +405,6 @@ class MarkCompactCollector {
                      AllocationSpace to_old_space,
                      SlotsBuffer** evacuation_slots_buffer);
 
-  bool TryPromoteObject(HeapObject* object, int object_size);
-
   void InvalidateCode(Code* code);
 
   void ClearMarkbits();
@@ -508,6 +502,10 @@ class MarkCompactCollector {
 
  private:
   class CompactionTask;
+  class EvacuateNewSpaceVisitor;
+  class EvacuateOldSpaceVisitor;
+  class EvacuateVisitorBase;
+  class HeapObjectVisitor;
   class SweeperTask;
 
   explicit MarkCompactCollector(Heap* heap);
@@ -704,10 +702,6 @@ class MarkCompactCollector {
   // 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);
 
   void EvacuateNewSpace();
 
@@ -729,7 +723,12 @@ class MarkCompactCollector {
 
   void EvacuateNewSpaceAndCandidates();
 
-  void VisitLiveObjects(Page* page, ObjectVisitor* visitor);
+  // Iterates through all live objects on a page using marking information.
+  // Returns whether all objects have successfully been visited.
+  bool VisitLiveObjects(MemoryChunk* page, HeapObjectVisitor* visitor,
+                        IterationMode mode);
+
+  void VisitLiveObjectsBody(Page* page, ObjectVisitor* visitor);
 
   void SweepAbortedPages();