Storage of ComputedStyle separate from LayoutObject.

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

Index: third_party/WebKit/Source/core/dom/Node.h
diff --git a/third_party/WebKit/Source/core/dom/Node.h b/third_party/WebKit/Source/core/dom/Node.h
index 1efce1287e4568084cc78c51e92915c2f06fee5a..ce1a326307bad22b89e5fea597ce3273a0cd14d0 100644
--- a/third_party/WebKit/Source/core/dom/Node.h
+++ b/third_party/WebKit/Source/core/dom/Node.h
@@ -511,13 +511,22 @@ public:
 
     // As layoutObject() includes a branch you should avoid calling it repeatedly in hot code paths.
     // Note that if a Node has a layoutObject, it's parentNode is guaranteed to have one as well.
-    LayoutObject* layoutObject() const { return hasRareData() ? m_data.m_rareData->layoutObject() : m_data.m_layoutObject; }
+    LayoutObject* layoutObject() const
+    {
+        if (hasRareData())
+            return m_data.m_rareData->layoutObject();
+        return hasLayoutObject() ? m_data.m_layoutObject : nullptr;
+    }
     void setLayoutObject(LayoutObject* layoutObject)
     {
         if (hasRareData())
             m_data.m_rareData->setLayoutObject(layoutObject);
         else
             m_data.m_layoutObject = layoutObject;
+        if (layoutObject)
+            setFlag(HasLayoutObjectFlag);

[esprehn, 2016/08/05 21:26:26]

setFlag(static_cast<bool>(layoutObject), HasLayoutObjectFlag);

then no branch. :)

[Bugs Nash, 2016/08/12 03:55:33]

Done

+        else
+            clearFlag(HasLayoutObjectFlag);
     }
 
     // Use these two methods with caution.
@@ -732,10 +741,12 @@ private:
         V0CustomElementFlag = 1 << 28,
         V0CustomElementUpgradedFlag = 1 << 29,
 
+        HasLayoutObjectFlag = 1 << 30,
+
         DefaultNodeFlags = IsFinishedParsingChildrenFlag | NeedsReattachStyleChange
     };
 
-    // 3 bits remaining.
+    // 1 bit remaining.

[esprehn, 2016/08/05 21:26:26]

thanks for fixing this :)

 
     bool getFlag(NodeFlags mask) const { return m_nodeFlags & mask; }
     void setFlag(bool f, NodeFlags mask) { m_nodeFlags = (m_nodeFlags & ~mask) | (-(int32_t)f & mask); }
@@ -767,6 +778,7 @@ protected:
 
     static void reattachWhitespaceSiblingsIfNeeded(Text* start);
 
+    bool hasLayoutObject() const { return getFlag(HasLayoutObjectFlag); }
     bool hasRareData() const { return getFlag(HasRareDataFlag); }
 
     NodeRareData* rareData() const;
@@ -825,6 +837,7 @@ private:
     // When a node has rare data we move the layoutObject into the rare data.
     union DataUnion {
         DataUnion() : m_layoutObject(nullptr) { }
+        ComputedStyle* m_computedStyle;
         // LayoutObjects are fully owned by their DOM node. See LayoutObject's
         // LIFETIME documentation section.
         LayoutObject* m_layoutObject;