Revert of [heap] delete Heap::LeftTrimFixedAray

src/heap/mark-compact.h

Index: src/heap/mark-compact.h
diff --git a/src/heap/mark-compact.h b/src/heap/mark-compact.h
index 322e8b83869295a338b6ba6e6b0b44d6291a1650..1ade4372f61d0909b1caad9b8d966935f06d0022 100644
--- a/src/heap/mark-compact.h
+++ b/src/heap/mark-compact.h
@@ -83,6 +83,12 @@ class Marking : public AllStatic {
     markbit.Clear();
   }
 
+  INLINE(static void GreyToWhite(MarkBit markbit)) {
+    DCHECK(IsGrey(markbit));
+    markbit.Clear();
+    markbit.Next().Clear();
+  }
+
   INLINE(static void BlackToGrey(MarkBit markbit)) {
     DCHECK(IsBlack(markbit));
     markbit.Next().Set();
@@ -113,6 +119,8 @@ class Marking : public AllStatic {
     markbit.Next().Set();
   }
 
+  static void TransferMark(Heap* heap, Address old_start, Address new_start);
+
 #ifdef DEBUG
   enum ObjectColor {
     BLACK_OBJECT,