Set ComputedStyle on Node and use that in buildOwnLayout()

third_party/WebKit/Source/core/dom/NodeComputedStyle.h

Index: third_party/WebKit/Source/core/dom/NodeComputedStyle.h
diff --git a/third_party/WebKit/Source/core/dom/NodeComputedStyle.h b/third_party/WebKit/Source/core/dom/NodeComputedStyle.h
index d7345264df9b5a75a8206a69643b3dba166c56d9..1ce6c888a28b70e6adb1d30f0c5ad9a87693f760 100644
--- a/third_party/WebKit/Source/core/dom/NodeComputedStyle.h
+++ b/third_party/WebKit/Source/core/dom/NodeComputedStyle.h
@@ -59,6 +59,27 @@ inline ComputedStyle* Node::mutableComputedStyle() const
     return m_data.m_computedStyle;
 }
 
+inline void Node::setComputedStyle(PassRefPtr<ComputedStyle> computedStyle)
+{
+    if (mutableComputedStyle() == computedStyle.get())
+        return;
+
+    if (hasRareData()) {
+        // If the DataUnion is an ElementRareData - set the ComputedStyle on that ElementRareData.
+        NodeRareData* rareData = this->rareData();
+        if (rareData->isElementRareData())
+            static_cast<ElementRareData*>(rareData)->setComputedStyle(computedStyle);
+    } else if (hasLayoutObject()) {
+        // If the DataUnion is a LayoutObject - set the ComputedStyle on that LayoutObject.
+        m_data.m_layoutObject->setStyleFromNodeOrElement(computedStyle);
+    } else {
+        // If the DataUnion is a ComputedStyle - make it point to the new ComputedStyle passed in.
+        if (m_data.m_computedStyle)
+            m_data.m_computedStyle->deref();
+        m_data.m_computedStyle = computedStyle.leakRef();
+    }
+}
+
 inline const ComputedStyle* Node::parentComputedStyle() const
 {
     if (isSlotOrActiveInsertionPoint())