[heap] Refactor MC and introduce MarkCompactCollectorBase

src/heap/mark-compact.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_HEAP_MARK_COMPACT_H_
 #define V8_HEAP_MARK_COMPACT_H_
 
 #include <deque>
 
 #include "src/base/bits.h"
@@ skipping 775 matching lines @@
 
   // Starts sweeping of spaces by contributing on the main thread and setting
   // up other pages for sweeping. Does not start sweeper tasks.
   void StartSweepSpaces();
   void StartSweepSpace(PagedSpace* space);
 
   void EvacuatePrologue();
   void EvacuateEpilogue();
   void EvacuatePagesInParallel();
 
-  // The number of parallel compaction tasks, including the main thread.
-  int NumberOfParallelCompactionTasks(int pages, intptr_t live_bytes);
-
   void EvacuateNewSpaceAndCandidates();
 
   void UpdatePointersAfterEvacuation();
 
   void ReleaseEvacuationCandidates();
 
 
 #ifdef DEBUG
   friend class MarkObjectVisitor;
   static void VisitObject(HeapObject* obj);
@@ skipping 61 matching lines @@
 
  private:
   MarkCompactCollector* collector_;
 };
 
 V8_EXPORT_PRIVATE const char* AllocationSpaceName(AllocationSpace space);
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_MARK_COMPACT_H_