Revert of Replace slots buffer with remembered set.

test/cctest/test-unboxed-doubles.cc

Index: test/cctest/test-unboxed-doubles.cc
diff --git a/test/cctest/test-unboxed-doubles.cc b/test/cctest/test-unboxed-doubles.cc
index cad32b725e190f6eb99eec3d19bb978ec408fe9f..f195a31c7972424294ca62bd78938634ae1b4603 100644
--- a/test/cctest/test-unboxed-doubles.cc
+++ b/test/cctest/test-unboxed-doubles.cc
@@ -12,6 +12,7 @@
 #include "src/factory.h"
 #include "src/field-type.h"
 #include "src/global-handles.h"
+#include "src/heap/slots-buffer.h"
 #include "src/ic/ic.h"
 #include "src/macro-assembler.h"
 #include "test/cctest/cctest.h"
@@ -1473,11 +1474,18 @@
   CHECK(Marking::IsBlack(Marking::MarkBitFrom(*obj_value)));
   CHECK(MarkCompactCollector::IsOnEvacuationCandidate(*obj_value));
 
-  // Trigger incremental write barrier, which should add a slot to remembered
-  // set.
-  {
+  // Trigger incremental write barrier, which should add a slot to |ec_page|'s
+  // slots buffer.
+  {
+    int slots_buffer_len = SlotsBuffer::SizeOfChain(ec_page->slots_buffer());
     FieldIndex index = FieldIndex::ForDescriptor(*map, tagged_descriptor);
-    obj->FastPropertyAtPut(index, *obj_value);
+    const int n = SlotsBuffer::kNumberOfElements + 10;
+    for (int i = 0; i < n; i++) {
+      obj->FastPropertyAtPut(index, *obj_value);
+    }
+    // Ensure that the slot was actually added to the |ec_page|'s slots buffer.
+    CHECK_EQ(slots_buffer_len + n,
+             SlotsBuffer::SizeOfChain(ec_page->slots_buffer()));
   }
 
   // Migrate |obj| to |new_map| which should shift fields and put the