Simple BlinkGC heap compaction.

third_party/WebKit/Source/wtf/Deque.h

 /*
  * Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 638 matching lines @@
            bufferEntry++)
         Allocator::template trace<VisitorDispatcher, T, VectorTraits<T>>(
             visitor, *const_cast<T*>(bufferEntry));
       const T* bufferEnd = m_buffer.buffer() + m_buffer.capacity();
       for (const T* bufferEntry = bufferBegin + m_start;
            bufferEntry != bufferEnd; bufferEntry++)
         Allocator::template trace<VisitorDispatcher, T, VectorTraits<T>>(
             visitor, *const_cast<T*>(bufferEntry));
     }
   }
-  if (m_buffer.hasOutOfLineBuffer())
+  if (m_buffer.hasOutOfLineBuffer()) {
     Allocator::markNoTracing(visitor, m_buffer.buffer());
+    Allocator::registerBackingStoreReference(visitor, m_buffer.bufferSlot());
+  }
 }
 
 template <typename T, size_t inlineCapacity, typename Allocator>
 inline void swap(Deque<T, inlineCapacity, Allocator>& a,
                  Deque<T, inlineCapacity, Allocator>& b) {
   a.swap(b);
 }
 
 }  // namespace WTF
 
 using WTF::Deque;
 
 #endif  // WTF_Deque_h