Storage of ComputedStyle separate from LayoutObject.

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 78872cdcf125b3139e08a8e7752e6eda40cfea34..4d7e9d6db263d9ab79aa80a8c2cc1f26f26cf6b5 100644
--- a/third_party/WebKit/Source/core/dom/NodeComputedStyle.h
+++ b/third_party/WebKit/Source/core/dom/NodeComputedStyle.h
@@ -25,8 +25,10 @@
 #ifndef NodeComputedStyle_h
 #define NodeComputedStyle_h
 
+#include "core/dom/ElementRareData.h"
 #include "core/dom/LayoutTreeBuilderTraversal.h"
 #include "core/dom/Node.h"
+#include "core/dom/NodeRareData.h"
 #include "core/dom/shadow/InsertionPoint.h"
 #include "core/html/HTMLOptGroupElement.h"
 #include "core/layout/LayoutObject.h"
@@ -41,14 +43,19 @@ inline const ComputedStyle* Node::computedStyle() const
 
 inline ComputedStyle* Node::mutableComputedStyle() const
 {
-    if (LayoutObject* layoutObject = this->layoutObject())
-        return layoutObject->mutableStyle();
+    if (hasLayoutObject())
+        return layoutObject()->mutableStyle();
     // <option> and <optgroup> can be styled even if they don't get layout objects,
     // so they store their style internally and return it through nonLayoutObjectComputedStyle().
     // We check here explicitly to avoid the virtual call in the common case.
     if (isHTMLOptGroupElement(*this) || isHTMLOptionElement(this))
         return nonLayoutObjectComputedStyle();
-    return 0;
+    if (hasRareData()) {
+        NodeRareData* rareData = this->rareData();
+        DCHECK(rareData->isElementRareData());
+        return static_cast<ElementRareData*>(rareData)->ensureComputedStyle();

[esprehn, 2016/07/18 20:58:52]

didn't you rename this recently?

[Bugs Nash, 2016/07/18 23:16:53]

yes, whoops forgot to rebase! Fixed

+    }
+    return m_data.m_computedStyle;
 }
 
 inline const ComputedStyle* Node::parentComputedStyle() const