Reland of [heap] Cleanup mark bit usage.

src/heap/spaces.cc

 // Copyright 2011 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/spaces.h"
 
 #include "src/base/bits.h"
 #include "src/base/platform/platform.h"
 #include "src/full-codegen/full-codegen.h"
 #include "src/heap/slots-buffer.h"
@@ skipping 3128 matching lines @@
   }
   return NULL;
 }
 
 
 void LargeObjectSpace::ClearMarkingStateOfLiveObjects() {
   LargePage* current = first_page_;
   while (current != NULL) {
     HeapObject* object = current->GetObject();
     MarkBit mark_bit = Marking::MarkBitFrom(object);
-    DCHECK(Marking::IsBlackOrGrey(mark_bit));
+    DCHECK(Marking::IsBlack(mark_bit));
     Marking::BlackToWhite(mark_bit);
     Page::FromAddress(object->address())->ResetProgressBar();
     Page::FromAddress(object->address())->ResetLiveBytes();
     current = current->next_page();
   }
 }
 
 
 void LargeObjectSpace::FreeUnmarkedObjects() {
   LargePage* previous = NULL;
   LargePage* current = first_page_;
   while (current != NULL) {
     HeapObject* object = current->GetObject();
     MarkBit mark_bit = Marking::MarkBitFrom(object);
-    if (Marking::IsBlackOrGrey(mark_bit)) {
+    DCHECK(!Marking::IsGrey(mark_bit));
+    if (Marking::IsBlack(mark_bit)) {
       previous = current;
       current = current->next_page();
     } else {
       LargePage* page = current;
       // Cut the chunk out from the chunk list.
       current = current->next_page();
       if (previous == NULL) {
         first_page_ = current;
       } else {
         previous->set_next_page(current);
@@ skipping 147 matching lines @@
     object->ShortPrint();
     PrintF("\n");
   }
   printf(" --------------------------------------\n");
   printf(" Marked: %x, LiveCount: %x\n", mark_size, LiveBytes());
 }
 
 #endif  // DEBUG
 }  // namespace internal
 }  // namespace v8