Remove calls to styleForLayoutObject() in LayoutTreeBuilder::style()

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

Index: third_party/WebKit/Source/core/dom/Element.cpp
diff --git a/third_party/WebKit/Source/core/dom/Element.cpp b/third_party/WebKit/Source/core/dom/Element.cpp
index 1bc8f3e7d3e1a98e6aef82217091da4ea9581c2e..db4811cf9cba15311573d19715c7df0976210cee 100644
--- a/third_party/WebKit/Source/core/dom/Element.cpp
+++ b/third_party/WebKit/Source/core/dom/Element.cpp
@@ -2020,11 +2020,15 @@ StyleRecalcChange Element::recalcOwnStyle(StyleRecalcChange change,
   }
 
   if (localChange == Reattach) {
+    // This mimicks Element::recalcStyleForLayout except it also stores the
+    // nextTextSibling information and sets the NeedsReattachLayoutTree flag.
     StyleReattachData styleReattachData;
     styleReattachData.computedStyle = std::move(newStyle);
     styleReattachData.nextTextSibling = nextTextSibling;
     document().addStyleReattachData(*this, styleReattachData);
     setNeedsReattachLayoutTree();
+    recalcShadowRootStylesForLayout();

[nainar, 2017/03/03 06:08:52]

This only goes over the descendants (ContainerNodes and ShadowRoot descendatnts)
only in the case we need Reattach. Should we maybe doing this in cases where
change >= UpdatePseudoElements to mimic the code in Element::recalcStyle()?

+    recalcDescendantStylesForLayout();
     return Reattach;
   }
 
@@ -2069,6 +2073,23 @@ StyleRecalcChange Element::recalcOwnStyle(StyleRecalcChange change,
   return localChange;
 }
 
+void Element::recalcStyleForLayout() {
+  if (!hasCustomStyleCallbacks()) {
+    StyleReattachData styleReattachData;
+    styleReattachData.computedStyle = styleForLayoutObject();
+    document().addStyleReattachData(*this, styleReattachData);
+  }
+  recalcShadowRootStylesForLayout();

[nainar, 2017/03/03 06:08:52]

Need to add a function here to deal with the relevant PseudoElement as well. 

void Element::recalcPseudoStyleForLayout(PseudoId pseudoId) {
  if (PseudoElement* element = pseudoElement(pseudoId))
      element->recalcStyleForLayout();
}

This comment applies to the code change above as well.

+  recalcDescendantStylesForLayout();
+}
+
+void Element::recalcShadowRootStylesForLayout() {
+  for (ShadowRoot* root = youngestShadowRoot(); root;
+       root = root->olderShadowRoot()) {
+      root->recalcDescendantStylesForLayout();
+  }
+}
+
 void Element::rebuildLayoutTree() {
   DCHECK(inActiveDocument());
   DCHECK(parentNode());