Storage of ComputedStyle separate from LayoutObject.

third_party/WebKit/Source/core/dom/Node.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 574 matching lines @@
     if (editableLevel == RichlyEditable)
         return false;
 
     // FIXME(dmazzoni): support ScopedAXObjectCache (crbug/489851).
     if (AXObjectCache* cache = document().existingAXObjectCache())
         return cache->rootAXEditableElement(this);
 
     return false;
 }
 
+void Node::setLayoutObject(LayoutObject* layoutObject)
+{
+    DCHECK(!layoutObject->style() || layoutObject->style() == computedStyle());
+    // this will probably cause a crash because of the <option> case
+    // if (layoutObject)
+        // layoutObject->setStyleInternal(computedStyle());
+    if (hasRareData()) {
+        if (hasLayoutObject()) {
+            if (this->layoutObject()->style()) {
+                if (layoutObject) {
+                    layoutObject->setStyleInternal(this->layoutObject()->mutableStyle());
+                } else {
+                    m_data.m_rareData->setComputedStyle(this->layoutObject()->mutableStyle());
+                }
+            }
+        } else if (m_data.m_rareData->computedStyle() && layoutObject) {
+            layoutObject->setStyleInternal(m_data.m_rareData->computedStyle());
+            m_data.m_rareData->setComputedStyle(nullptr);
+        }
+        m_data.m_rareData->setLayoutObject(layoutObject);
+    } else {
+        if (hasLayoutObject()) {
+            if (this->layoutObject()->style()) {
+                if (layoutObject) {
+                    layoutObject->setStyleInternal(this->layoutObject()->mutableStyle());
+                    m_data.m_layoutObject = layoutObject;
+                } else {
+                    m_data.m_computedStyle = this->layoutObject()->mutableStyle();
+                }
+            } else {
+                m_data.m_layoutObject = layoutObject;
+            }
+        } else {
+            if (m_data.m_computedStyle && layoutObject) {
+                layoutObject->setStyleInternal(m_data.m_computedStyle);
+            }
+            m_data.m_layoutObject = layoutObject;
+        }
+        // if (!(hasLayoutObject() && this->layoutObject()->style() && !layoutObject))
+        //     m_data.m_layoutObject = layoutObject;
+    }
+
+    if (layoutObject) {
+        setFlag(HasLayoutObjectFlag);
+    } else {
+        clearFlag(HasLayoutObjectFlag);
+    }
+}
+
+void Node::clearStyleAndLayoutObject()
+{
+    if (hasRareData()) {
+        m_data.m_rareData->setLayoutObject(nullptr);
+        m_data.m_rareData->setComputedStyle(nullptr);
+    } else {
+        // Will nullify the data regardless of whether it is a LayoutObject or a ComputedStyle
+        m_data.m_layoutObject = nullptr;
+    }
+    clearFlag(HasLayoutObjectFlag);
+}
+
 LayoutBox* Node::layoutBox() const
 {
     LayoutObject* layoutObject = this->layoutObject();
     return layoutObject && layoutObject->isBox() ? toLayoutBox(layoutObject) : nullptr;
 }
 
 LayoutBoxModelObject* Node::layoutBoxModelObject() const
 {
     LayoutObject* layoutObject = this->layoutObject();
     return layoutObject && layoutObject->isBoxModelObject() ? toLayoutBoxModelObject(layoutObject) : nullptr;
@@ skipping 319 matching lines @@
         cache->updateCacheAfterNodeIsAttached(this);
 }
 
 void Node::detach(const AttachContext& context)
 {
     DCHECK(document().lifecycle().stateAllowsDetach());
     DocumentLifecycle::DetachScope willDetach(document().lifecycle());
 
     if (layoutObject())
         layoutObject()->destroyAndCleanupAnonymousWrappers();
-    setLayoutObject(nullptr);
+    clearStyleAndLayoutObject();
     setStyleChange(NeedsReattachStyleChange);
     clearChildNeedsStyleInvalidation();
 }
 
 void Node::reattachWhitespaceSiblingsIfNeeded(Text* start)
 {
     ScriptForbiddenScope forbidScriptDuringRawIteration;
     for (Node* sibling = start; sibling; sibling = sibling->nextSibling()) {
         if (sibling->isTextNode() && toText(sibling)->containsOnlyWhitespace()) {
             bool hadLayoutObject = !!sibling->layoutObject();
@@ skipping 1530 matching lines @@
 
 void showNodePath(const blink::Node* node)
 {
     if (node)
         node->showNodePathForThis();
     else
         fprintf(stderr, "Cannot showNodePath for (nil)\n");
 }
 
 #endif