Reland of "🏄 [heap] Add page evacuation mode for new->old"

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 610 matching lines @@
 
   EmbedderHeapTracer* embedder_heap_tracer() { return embedder_heap_tracer_; }
 
   bool UsingEmbedderHeapTracer() { return embedder_heap_tracer(); }
 
   void TracePossibleWrapper(JSObject* js_object);
 
   void RegisterExternallyReferencedObject(Object** object);
 
  private:
+  class EvacuateNewSpacePageVisitor;
   class EvacuateNewSpaceVisitor;
   class EvacuateOldSpaceVisitor;
   class EvacuateRecordOnlyVisitor;
   class EvacuateVisitorBase;
   class HeapObjectVisitor;
 
-  typedef std::vector<Page*> SweepingList;
-
   explicit MarkCompactCollector(Heap* heap);
 
   bool WillBeDeoptimized(Code* code);
   void ClearInvalidRememberedSetSlots();
 
   void ComputeEvacuationHeuristics(int area_size,
                                    int* target_fragmentation_percent,
                                    int* max_evacuated_bytes);
 
 #ifdef DEBUG
@@ skipping 172 matching lines @@
 
   // The number of parallel compaction tasks, including the main thread.
   int NumberOfParallelCompactionTasks(int pages, intptr_t live_bytes);
 
   void EvacuateNewSpaceAndCandidates();
 
   void UpdatePointersAfterEvacuation();
 
   // 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,
+  template <class Visitor>
+  bool VisitLiveObjects(MemoryChunk* page, Visitor* visitor,
                         IterationMode mode);
 
   void VisitLiveObjectsBody(Page* page, ObjectVisitor* visitor);
 
   void RecomputeLiveBytes(MemoryChunk* page);
 
   void ReleaseEvacuationCandidates();
 
   // Starts sweeping of a space by contributing on the main thread and setting
   // up other pages for sweeping.
@@ skipping 50 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_MARK_COMPACT_H_