(Only) poison unmarked heap objects prior to sweeping.

third_party/WebKit/Source/platform/heap/BlinkGC.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BlinkGC_h
 #define BlinkGC_h
 
 // BlinkGC.h is a file that defines common things used by Blink GC.
 
 #include "platform/PlatformExport.h"
@@ skipping 79 matching lines @@
         Vector3ArenaIndex,
         Vector4ArenaIndex,
         InlineVectorArenaIndex,
         HashTableArenaIndex,
         FOR_EACH_TYPED_ARENA(TypedArenaEnumName)
         LargeObjectArenaIndex,
         // Values used for iteration of heap segments.
         NumberOfArenas,
     };
 
-#if defined(ADDRESS_SANITIZER)
-    // Heaps can have their object payloads be poisoned, or cleared
-    // of their poisoning.
-    enum Poisoning {
-        SetPoison,
-        ClearPoison,
-    };
-
-    enum ObjectsToPoison {
-        UnmarkedOnly,
-        MarkedAndUnmarked,
-    };
-#endif
-
     enum V8GCType {
         V8MinorGC,
         V8MajorGC,
     };
 };
 
 } // namespace blink
 
 #endif