Revert of Reland concurrent sweeping of code space.

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 b2a41ce1f6733d2e47d72da51971454c61dfaf12..e212c9501dda037d90463adb6de3afbc79a4bc15 100644
--- a/src/heap/mark-compact.h
+++ b/src/heap/mark-compact.h
@@ -691,8 +691,6 @@
 
   void EnsureSweepingCompleted();
 
-  void EnsureSweepingCompleted(Page* page, PagedSpace* space);
-
   // If sweeper threads are not active this method will return true. If
   // this is a latency issue we should be smarter here. Otherwise, it will
   // return true if the sweeper threads are done processing the pages.
@@ -969,7 +967,6 @@
   List<Page*> evacuation_candidates_;
 
   base::SmartPointer<FreeList> free_list_old_space_;
-  base::SmartPointer<FreeList> free_list_code_space_;
 
   friend class Heap;
 };