Revert of [heap] Make non-atomic markbit operations consistent with atomic ones.

src/heap/heap.cc

 // 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.
 
 #include "src/heap/heap.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/assembler-inl.h"
 #include "src/ast/context-slot-cache.h"
@@ skipping 4246 matching lines @@
           addr += obj->Size();
         }
       }
     }
   }
 }
 
 void Heap::NotifyObjectLayoutChange(HeapObject* object,
                                     const DisallowHeapAllocation&) {
   if (FLAG_incremental_marking && incremental_marking()->IsMarking()) {
-    incremental_marking()->WhiteToGreyAndPush(object);
+    incremental_marking()->MarkGrey(object);
   }
 #ifdef VERIFY_HEAP
   DCHECK(pending_layout_change_object_ == nullptr);
   pending_layout_change_object_ = object;
 #endif
 }
 
 #ifdef VERIFY_HEAP
 void Heap::VerifyObjectLayoutChange(HeapObject* object, Map* new_map) {
   if (pending_layout_change_object_ == nullptr) {
@@ skipping 543 matching lines @@
       slot_address += kPointerSize;
     }
   }
 
   inline void VisitCodeEntry(JSFunction* host,
                              Address code_entry_slot) override {
     // Black allocation requires us to process objects referenced by
     // promoted objects.
     if (heap_->incremental_marking()->black_allocation()) {
       Code* code = Code::cast(Code::GetObjectFromEntryAddress(code_entry_slot));
-      heap_->incremental_marking()->WhiteToGreyAndPush(code);
+      heap_->incremental_marking()->MarkGrey(code);
     }
   }
 
  private:
   Heap* heap_;
   bool record_slots_;
 };
 
 void Heap::IterateAndScavengePromotedObject(HeapObject* target, int size) {
   // We are not collecting slots on new space objects during mutation
@@ skipping 773 matching lines @@
   }
 }
 
 void Heap::RegisterExternallyReferencedObject(Object** object) {
   // The embedder is not aware of whether numbers are materialized as heap
   // objects are just passed around as Smis.
   if (!(*object)->IsHeapObject()) return;
   HeapObject* heap_object = HeapObject::cast(*object);
   DCHECK(Contains(heap_object));
   if (FLAG_incremental_marking_wrappers && incremental_marking()->IsMarking()) {
-    incremental_marking()->WhiteToGreyAndPush(heap_object);
+    incremental_marking()->MarkGrey(heap_object);
   } else {
     DCHECK(mark_compact_collector()->in_use());
     mark_compact_collector()->MarkObject(heap_object);
   }
 }
 
 void Heap::TearDown() {
 #ifdef VERIFY_HEAP
   if (FLAG_verify_heap) {
     Verify();
@@ skipping 747 matching lines @@
     case LO_SPACE:
       return "LO_SPACE";
     default:
       UNREACHABLE();
   }
   return NULL;
 }
 
 }  // namespace internal
 }  // namespace v8