Reland "Keep track of array buffers in new space separately"

src/heap/mark-compact.cc

Index: src/heap/mark-compact.cc
diff --git a/src/heap/mark-compact.cc b/src/heap/mark-compact.cc
index 7494330263ea37c0ec0eb32fba3f1b3a19ceaff2..9a4e88d9c4c8be444253f82aea323b241242febd 100644
--- a/src/heap/mark-compact.cc
+++ b/src/heap/mark-compact.cc
@@ -3041,6 +3041,10 @@ bool MarkCompactCollector::TryPromoteObject(HeapObject* object,
   AllocationResult allocation = old_space->AllocateRaw(object_size, alignment);
   if (allocation.To(&target)) {
     MigrateObject(target, object, object_size, old_space->identity());
+    // If we end up needing more special cases, we should factor this out.
+    if (V8_UNLIKELY(target->IsJSArrayBuffer())) {
+      heap()->PromoteArrayBuffer(target);
+    }
     heap()->IncrementPromotedObjectsSize(object_size);
     return true;
   }
@@ -4367,7 +4371,6 @@ void MarkCompactCollector::SweepSpaces() {
 #ifdef DEBUG
   state_ = SWEEP_SPACES;
 #endif
-  heap()->FreeDeadArrayBuffers();
 
   MoveEvacuationCandidatesToEndOfPagesList();
 
@@ -4395,6 +4398,8 @@ void MarkCompactCollector::SweepSpaces() {
 
   EvacuateNewSpaceAndCandidates();
 
+  heap()->FreeDeadArrayBuffers(false);
+
   // ClearNonLiveReferences depends on precise sweeping of map space to
   // detect whether unmarked map became dead in this collection or in one
   // of the previous ones.