Oilpan: DOM wrappers don't need to keep persistent handles

Source/platform/heap/Handle.cpp

-// Copyright 2014 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.
-
-#include "config.h"
-#include "platform/heap/Handle.h"
-
-namespace blink {
-
-bool WrapperPersistentRegion::removeIfNotLast(WrapperPersistentRegion** headPtr)
-{
-    ASSERT(!m_count);
-    // We are the last region in the list if both the region's m_prev and
-    // m_next are 0.
-    if (!m_prev && !m_next)
-        return false;
-    if (m_prev) {
-        m_prev->m_next = m_next;
-    } else {
-        ASSERT(*headPtr == this);
-        *headPtr = m_next;
-    }
-    if (m_next)
-        m_next->m_prev = m_prev;
-    m_prev = 0;
-    m_next = 0;
-    return true;
-}
-
-void WrapperPersistentRegion::insertHead(WrapperPersistentRegion** headPtr, WrapperPersistentRegion* newHead)
-{
-    ASSERT(headPtr);
-    WrapperPersistentRegion* oldHead = *headPtr;
-    if (oldHead) {
-        ASSERT(!oldHead->m_prev);
-        oldHead->m_prev = newHead;
-    }
-    newHead->m_prev = 0;
-    newHead->m_next = oldHead;
-    *headPtr = newHead;
-}
-
-WrapperPersistentRegion* WrapperPersistentRegion::removeHead(WrapperPersistentRegion** headPtr)
-{
-    // We only call this if there is at least one element in the list.
-    ASSERT(headPtr && *headPtr);
-    WrapperPersistentRegion* oldHead = *headPtr;
-    ASSERT(!oldHead->m_prev);
-    *headPtr = oldHead->m_next;
-    oldHead->m_next = 0;
-    ASSERT(!(*headPtr) || (*headPtr)->m_prev == oldHead);
-    if (*headPtr)
-        (*headPtr)->m_prev = 0;
-    return oldHead;
-}
-
-Address WrapperPersistentRegion::outOfLineAllocate(ThreadState* state, WrapperPersistentRegion** regionPtr)
-{
-    Address persistentSlot = 0;
-    // The caller has already tried allocating in the passed-in region, start
-    // from the next.
-    for (WrapperPersistentRegion* current = (*regionPtr)->m_next; current; current = current->m_next) {
-        persistentSlot = current->allocate();
-        if (persistentSlot) {
-            *regionPtr = current;
-            return persistentSlot;
-        }
-    }
-    ASSERT(!persistentSlot);
-    WrapperPersistentRegion* newRegion = state->takeWrapperPersistentRegion();
-    persistentSlot = newRegion->allocate();
-    *regionPtr = newRegion;
-    ASSERT(persistentSlot);
-    return persistentSlot;
-}
-
-}