Revert of [heap] Remove black pages and use black areas instead.

src/heap/spaces.h

Index: src/heap/spaces.h
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index 326a59916b4c1fb6a26bd7085e78f17ccb11afa7..84c6d68bcc162051d2e5336105554eea003b4be5 100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -249,6 +249,11 @@
     // within the new space during evacuation.
     PAGE_NEW_NEW_PROMOTION,
 
+    // A black page has all mark bits set to 1 (black). A black page currently
+    // cannot be iterated because it is not swept. Moreover live bytes are also
+    // not updated.
+    BLACK_PAGE,
+
     // This flag is intended to be used for testing. Works only when both
     // FLAG_stress_compaction and FLAG_manual_evacuation_candidates_selection
     // are set. It forces the page to become an evacuation candidate at next
@@ -423,10 +428,12 @@
 
   int LiveBytes() {
     DCHECK_LE(static_cast<unsigned>(live_byte_count_), size_);
+    DCHECK(!IsFlagSet(BLACK_PAGE) || live_byte_count_ == 0);
     return live_byte_count_;
   }
 
   void SetLiveBytes(int live_bytes) {
+    if (IsFlagSet(BLACK_PAGE)) return;
     DCHECK_GE(live_bytes, 0);
     DCHECK_LE(static_cast<size_t>(live_bytes), size_);
     live_byte_count_ = live_bytes;
@@ -2065,12 +2072,14 @@
     allocation_info_.Reset(top, limit);
   }
 
-  void SetAllocationInfo(Address top, Address limit);
-
   // Empty space allocation info, returning unused area to free list.
-  void EmptyAllocationInfo();
-
-  void MarkAllocationInfoBlack();
+  void EmptyAllocationInfo() {
+    // Mark the old linear allocation area with a free space map so it can be
+    // skipped when scanning the heap.
+    int old_linear_size = static_cast<int>(limit() - top());
+    Free(top(), old_linear_size);
+    SetTopAndLimit(NULL, NULL);
+  }
 
   void Allocate(int bytes) { accounting_stats_.AllocateBytes(bytes); }