Reland "Merge cellspace into old pointer space"

src/heap/incremental-marking.cc

Index: src/heap/incremental-marking.cc
diff --git a/src/heap/incremental-marking.cc b/src/heap/incremental-marking.cc
index dfcd68a3d34326388682265bf937aadf340991c3..8edac8254dfd1b816b3af58b9cfc0bc3ed0e634e 100644
--- a/src/heap/incremental-marking.cc
+++ b/src/heap/incremental-marking.cc
@@ -301,10 +301,6 @@ void IncrementalMarking::SetOldSpacePageFlags(MemoryChunk* chunk,
         chunk->size() > static_cast<size_t>(Page::kPageSize) && is_compacting) {
       chunk->SetFlag(MemoryChunk::RESCAN_ON_EVACUATION);
     }
-  } else if (chunk->owner()->identity() == CELL_SPACE ||
-             chunk->scan_on_scavenge()) {
-    chunk->ClearFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING);
-    chunk->ClearFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING);
   } else {
     chunk->ClearFlag(MemoryChunk::POINTERS_TO_HERE_ARE_INTERESTING);
     chunk->SetFlag(MemoryChunk::POINTERS_FROM_HERE_ARE_INTERESTING);
@@ -346,7 +342,6 @@ void IncrementalMarking::DeactivateIncrementalWriteBarrierForSpace(
 
 void IncrementalMarking::DeactivateIncrementalWriteBarrier() {
   DeactivateIncrementalWriteBarrierForSpace(heap_->old_space());
-  DeactivateIncrementalWriteBarrierForSpace(heap_->cell_space());
   DeactivateIncrementalWriteBarrierForSpace(heap_->map_space());
   DeactivateIncrementalWriteBarrierForSpace(heap_->code_space());
   DeactivateIncrementalWriteBarrierForSpace(heap_->new_space());
@@ -379,7 +374,6 @@ void IncrementalMarking::ActivateIncrementalWriteBarrier(NewSpace* space) {
 
 void IncrementalMarking::ActivateIncrementalWriteBarrier() {
   ActivateIncrementalWriteBarrier(heap_->old_space());
-  ActivateIncrementalWriteBarrier(heap_->cell_space());
   ActivateIncrementalWriteBarrier(heap_->map_space());
   ActivateIncrementalWriteBarrier(heap_->code_space());
   ActivateIncrementalWriteBarrier(heap_->new_space());