Reland "Remove children from HistoryNodes that redirect during back/forward navigation"

Source/core/page/HistoryController.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * 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
@@ skipping 64 matching lines @@
     : m_entry(entry)
     , m_value(value)
 {
     m_entry->m_framesToItems.add(value->targetFrameID(), this);
     String target = value->target();
     if (target.isNull())
         target = emptyString();
     m_entry->m_uniqueNamesToItems.add(target, this);
 }
 
+void HistoryNode::removeChildren()
+{
+    // FIXME: This is inefficient. Figure out a cleaner way to ensure this HistoryNode isn't cached anywhere.
+    for (unsigned i = 0; i < m_children.size(); i++) {
+        m_children[i]->removeChildren();
+
+        HashMap<uint64_t, HistoryNode*>::iterator framesEnd = m_entry->m_framesToItems.end();
+        HashMap<String, HistoryNode*>::iterator uniqueNamesEnd = m_entry->m_uniqueNamesToItems.end();
+        for (HashMap<uint64_t, HistoryNode*>::iterator it = m_entry->m_framesToItems.begin(); it != framesEnd; ++it) {
+            if (it->value == m_children[i])
+                m_entry->m_framesToItems.remove(it);
+        }
+        for (HashMap<String, HistoryNode*>::iterator it = m_entry->m_uniqueNamesToItems.begin(); it != uniqueNamesEnd; ++it) {
+            if (it->value == m_children[i])
+                m_entry->m_uniqueNamesToItems.remove(it);
+        }
+    }
+    m_children.clear();
+}
+
 HistoryEntry::HistoryEntry(HistoryItem* root)
 {
     m_root = HistoryNode::create(this, root);
 }
 
 PassOwnPtr<HistoryEntry> HistoryEntry::create(HistoryItem* root)
 {
     return adoptPtr(new HistoryEntry(root));
 }
 
@@ skipping 175 matching lines @@
     if (!m_previousEntry)
         return 0;
     return itemForExport(m_previousEntry->rootHistoryNode());
 }
 
 HistoryItem* HistoryController::itemForNewChildFrame(Frame* frame) const
 {
     return m_currentEntry ? m_currentEntry->itemForFrame(frame) : 0;
 }
 
+void HistoryController::removeChildrenForRedirect(Frame* frame)
+{
+    if (!m_provisionalEntry)
+        return;
+    if (HistoryNode* node = m_provisionalEntry->historyNodeForFrame(frame))
+        node->removeChildren();
+}
+
 void HistoryController::createNewBackForwardItem(Frame* targetFrame, HistoryItem* item, bool clipAtTarget)
 {
     RefPtr<HistoryItem> newItem = item;
     if (!m_currentEntry) {
         m_currentEntry = HistoryEntry::create(newItem.get());
     } else {
         HistoryItem* oldItem = m_currentEntry->itemForFrame(targetFrame);
         if (!clipAtTarget && oldItem)
             newItem->setDocumentSequenceNumber(oldItem->documentSequenceNumber());
         m_previousEntry = m_currentEntry.release();
         m_currentEntry = m_previousEntry->cloneAndReplace(newItem.get(), clipAtTarget, targetFrame, m_page);
     }
 }
 
 } // namespace WebCore