Treat links that organize weak objects weakly.

src/heap/mark-compact.h

 // Copyright 2012 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.
 
 #ifndef V8_HEAP_MARK_COMPACT_H_
 #define V8_HEAP_MARK_COMPACT_H_
 
 #include "src/base/bits.h"
 #include "src/heap/spaces.h"
 
@@ skipping 498 matching lines @@
         HeapObject::RawField(candidate, JSFunction::kNextFunctionLinkOffset));
   }
 
   static JSFunction* GetNextCandidate(JSFunction* candidate) {
     Object* next_candidate = candidate->next_function_link();
     return reinterpret_cast<JSFunction*>(next_candidate);
   }
 
   static void SetNextCandidate(JSFunction* candidate,
                                JSFunction* next_candidate) {
-    candidate->set_next_function_link(next_candidate);
+    candidate->set_next_function_link(next_candidate,
+                                      UPDATE_WEAK_WRITE_BARRIER);
   }
 
   static void ClearNextCandidate(JSFunction* candidate, Object* undefined) {
     DCHECK(undefined->IsUndefined());
     candidate->set_next_function_link(undefined, SKIP_WRITE_BARRIER);
   }
 
   static SharedFunctionInfo* GetNextCandidate(SharedFunctionInfo* candidate) {
     Object* next_candidate = candidate->code()->gc_metadata();
     return reinterpret_cast<SharedFunctionInfo*>(next_candidate);
@@ skipping 487 matching lines @@
  private:
   MarkCompactCollector* collector_;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_MARK_COMPACT_H_