Revert of Simple BlinkGC heap compaction.

third_party/WebKit/Source/wtf/LinkedHashSet.h

Index: third_party/WebKit/Source/wtf/LinkedHashSet.h
diff --git a/third_party/WebKit/Source/wtf/LinkedHashSet.h b/third_party/WebKit/Source/wtf/LinkedHashSet.h
index 019ef73182e1b3e544afb52651a7fecac7d20ffb..0a2235a0eeb054af291152ea363a058e78dce483 100644
--- a/third_party/WebKit/Source/wtf/LinkedHashSet.h
+++ b/third_party/WebKit/Source/wtf/LinkedHashSet.h
@@ -299,13 +299,6 @@
   template <typename VisitorDispatcher>
   void trace(VisitorDispatcher visitor) {
     m_impl.trace(visitor);
-    // Should the underlying table be moved by GC, register a callback
-    // that fixes up the interior pointers that the (Heap)LinkedHashSet keeps.
-    if (m_impl.m_table) {
-      Allocator::registerBackingStoreCallback(
-          visitor, m_impl.m_table, moveBackingCallback,
-          reinterpret_cast<void*>(&m_anchor));
-    }
   }
 
   int64_t modifications() const { return m_impl.modifications(); }
@@ -338,50 +331,6 @@
   }
   const_reverse_iterator makeConstReverseIterator(const Node* position) const {
     return const_reverse_iterator(position, this);
-  }
-
-  static void moveBackingCallback(void* anchor,
-                                  void* from,
-                                  void* to,
-                                  size_t size) {
-    // Note: the hash table move may have been overlapping; linearly scan the
-    // entire table and fixup interior pointers into the old region with
-    // correspondingly offset ones into the new.
-    size_t tableSize = size / sizeof(Node);
-    Node* table = reinterpret_cast<Node*>(to);
-    NodeBase* fromStart = reinterpret_cast<NodeBase*>(from);
-    NodeBase* fromEnd =
-        reinterpret_cast<NodeBase*>(reinterpret_cast<uintptr_t>(from) + size);
-    for (Node* element = table + tableSize - 1; element >= table; element--) {
-      Node& node = *element;
-      if (ImplType::isEmptyOrDeletedBucket(node))
-        continue;
-      if (node.m_next >= fromStart && node.m_next < fromEnd) {
-        size_t diff = reinterpret_cast<uintptr_t>(node.m_next) -
-                      reinterpret_cast<uintptr_t>(from);
-        node.m_next =
-            reinterpret_cast<NodeBase*>(reinterpret_cast<uintptr_t>(to) + diff);
-      }
-      if (node.m_prev >= fromStart && node.m_prev < fromEnd) {
-        size_t diff = reinterpret_cast<uintptr_t>(node.m_prev) -
-                      reinterpret_cast<uintptr_t>(from);
-        node.m_prev =
-            reinterpret_cast<NodeBase*>(reinterpret_cast<uintptr_t>(to) + diff);
-      }
-    }
-    NodeBase* anchorNode = reinterpret_cast<NodeBase*>(anchor);
-    if (anchorNode->m_next >= fromStart && anchorNode->m_next < fromEnd) {
-      size_t diff = reinterpret_cast<uintptr_t>(anchorNode->m_next) -
-                    reinterpret_cast<uintptr_t>(from);
-      anchorNode->m_next =
-          reinterpret_cast<NodeBase*>(reinterpret_cast<uintptr_t>(to) + diff);
-    }
-    if (anchorNode->m_prev >= fromStart && anchorNode->m_prev < fromEnd) {
-      size_t diff = reinterpret_cast<uintptr_t>(anchorNode->m_prev) -
-                    reinterpret_cast<uintptr_t>(from);
-      anchorNode->m_prev =
-          reinterpret_cast<NodeBase*>(reinterpret_cast<uintptr_t>(to) + diff);
-    }
   }
 
   ImplType m_impl;