[heap] Use cancelable tasks during compaction.

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 "src/base/bits.h"
 #include "src/heap/spaces.h"
 
@@ skipping 700 matching lines @@
       SlotsBuffer* evacuation_slots_buffer);
 
   void EvacuatePages(CompactionSpaceCollection* compaction_spaces,
                      SlotsBuffer** evacuation_slots_buffer);
 
   void EvacuatePagesInParallel();
 
   // The number of parallel compaction tasks, including the main thread.
   int NumberOfParallelCompactionTasks();
 
-  void WaitUntilCompactionCompleted();
-
   void EvacuateNewSpaceAndCandidates();
 
   void VisitLiveObjects(Page* page, ObjectVisitor* visitor);
 
   void SweepAbortedPages();
 
   void ReleaseEvacuationCandidates();
 
   // Moves the pages of the evacuation_candidates_ list to the end of their
   // corresponding space pages list.
@@ skipping 57 matching lines @@
 
   // True if parallel compaction is currently in progress.
   bool compaction_in_progress_;
 
   // Semaphore used to synchronize sweeper tasks.
   base::Semaphore pending_sweeper_tasks_semaphore_;
 
   // Semaphore used to synchronize compaction tasks.
   base::Semaphore pending_compaction_tasks_semaphore_;
 
-  // Number of active compaction tasks (including main thread).
-  intptr_t concurrent_compaction_tasks_active_;
-
   friend class Heap;
 };
 
 
 class MarkBitCellIterator BASE_EMBEDDED {
  public:
   explicit MarkBitCellIterator(MemoryChunk* chunk) : chunk_(chunk) {
     last_cell_index_ = Bitmap::IndexToCell(Bitmap::CellAlignIndex(
         chunk_->AddressToMarkbitIndex(chunk_->area_end())));
     cell_base_ = chunk_->area_start();
@@ skipping 44 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_MARK_COMPACT_H_